BRAKE EXHAUST CHASSIS & MORE Compliments of:

Transcription

1 BRAKE EXHAUST CHASSIS & MORE Compliments of:

2 Examining Chevrolet s Volt Rear Brake System...1 Particle Buildup on Unitized Hub & Bearing Wheel-Speed Sensors...4 Bench Bleeding & Pressure Testing Master Cylinders...7 Shaking Brake Pedals...11 Braking & Shaking: Are You Sure Your Know the Cause?...13 Brake Quality & Codes Are Important...15 Selecting Training for Your Shop...19 Irregular & Unusual Pad Wear...21 Some F-150s Don t Want to Pass Shiny Objects!...23 Electronic Parking Brakes: Nothing New Any More!...24 Preventing Fast Brake-Pad Wear in Hard-working GM/Ram Trucks..25 Make Sure that Circuit Has a Good Ground Connection!...27 Technician s Dictionary...28 Your Favorite Shop Tools

3 phototechby Ron Henningsen Undercar Digest Technical Editor Examining Chevrolet s Volt Rear Brake System Chevy Volt, GM s electric car, has a hydraulic braking system that is similar in its basic configuration to many other systems, but has a few hidden features. This Photo Tech will explain some of those features as well as a new vibration-damper system. As you will observe, when working on the brake system of a late-model car, particularly one as advanced as a vehicle like the Chevy Volt, it s important to take a minute to look around and see what s going on and observe the variations. By understanding this car s vibration damper, the fixed location of the pads and chamfer on the pads, you ll be able to diagnose problems in the future should someone not do work correctly or part of the system fails. Special thanks to Assistant Professor Alexander Richards and his students at the Automotive Technology Management department at University of Central Missouri in Warrensburg 1 2 A student is shown with one of the many donated cars of the Automotive Technology Management department. 3 4 You can always tell a true Volt by the plug-in on the left front fender. Some people have faked cars in order to drive in electric or high-vehicle-occupancy lanes. 6 This Chevy Volt drives a bit differently from other cars. It also has a braking system with many innovative features. To access the rear brake system, do what you always do, pull one of the rear wheels. 5 You will notice that, as with many latemodel vehicles, the rotor has what appears to be a substantial coating on it. This can be good or bad, depending upon the type of brake pads and rotor used. The electronic parking-brake-actuation system is controlled by a motor that is near the gas tank and out of sight. Although it is fairly trouble free, locating it is difficult unless you have a schematic. 1

4 7 If you look at the rear brake system you ll see a harmonic device attached to the lower caliper-mounting bolt on the rear. 8 This device is removed by lifting the rubber endcap plug and using a torque socket to unscrew it from the caliper-mounting bolt Although you would not normally disassemble this unit for service, if you have a noise problem and think the damper has failed, you can take it apart by removing the three torx screws on the back side of the damper. The vibration damper has been removed in this photo. Note that the caliper-mounting pin has an extension-threaded stud to accept the vibration damper. 11 The damper consists of a forward and backward metal die-cast housing, along with a silicone disc over the moveable center of the front housing. If this unit has become contaminated or if the silicone disc has failed, you may have a vibration issue. While you are working on this system, carefully inspect the rotor. This particular vehicle had an excessive buildup of transfer layer of material on the rotor. Although it was not causing any noise-related problems, you would have no way of knowing if the coefficient of friction is what it should be or if excessive pedal pressure is required to correctly stop the vehicle. 13 The mounting bolt is removed using a deep socket or box-end wrench. Note that this is a special stud with a built-in hex on it and one that is not easily replaced if dropped or lost. 2

5 phototech 14 After removing both caliper mounting bolts, lift the caliper off the pads and lower the assembly. 15 Following commonsense safeshop practices, always hang the caliper on a hook. Don t rely upon some precarious placement or mounting position to hold the caliper and keep it from dropping or hanging by the hose Note that both the inner and outer pads have a very high degree of chamfer on one side. One has more than the other. If you look at the backside of the pads, you will see that they are labeled inboard and outboard with a directional arrow. This is to accommodate the chamfer that is visible in this photo. Be sure to install them correctly or you may have a noise- or chatter-related issue To disconnect the rotor, remove the retaining screw that holds it onto the axle flange. Then remove the rotor from the wheel studs. Note that this lowmileage Chevy Volt from a Rust Belt area has rust and scale starting to build up on the face of the flange of the hub. Also note that there is an inboard and outboard contact area that prevents immediate rust jacking from taking place. This design feature prevents some of the contact surfaces from having future problems. 20 If you remove the wheelspeed sensor from this vehicle, as with all late-model wheel-speed sensors with a magnetoresistant unit, you will see that the newer style shells are oblong in shape. 3

6 phototechby Ron Henningsen Undercar Digest Technical Editor Particle Buildup on Unitized Hub & Bearing Wheel-Speed Sensors By Ron Henningsen Undercar Digest Technical Editor Over the years there has been a variety of problems involving fuzz or metallic particle buildup on wheel-speed sensors. In the 80s and early 90s it happened on analog wheel-speed sensors and today it s happening on magneto-resistive (MR) wheel-speed sensors that generate a square wave. In any situation, the particle buildup distorts the signal, causing a problem. The controller computer may sense this as a complete signal failure, a signal out of phase or a wide variety of other problems that usually set a code for a wheel-speed sensor fault If a vehicle is diagnosed with a wheelspeed sensor problem, the first step is to disassemble the brake system as shown in order to remove the unitized hub-and-bearing assembly. Although extremely basic, don t forget to hang the caliper by a hook. Don t just place it on something so that if it falls it stretches the brake hose. This is a prime example of why you don t just rip something apart as quickly as you can. Look at the transfer layer on this rotor. What caused it? Is it a problem? Should it be addressed in addition to being repaired? These questions should be answered before removing and reinstalling the rotor. 4 Note the routing of the wheelspeed sensor wires and make sure they are reinstalled in the same position. Failure to do so may cause physical contact with a suspension component or wheel and lead to an additional failure of the wiring. 5 After removing the brake assembly and the bolts holding the unitized hub-and-bearing assembly and the CV axle nut, remove the unitized hub-and-bearing assembly. Depending upon where the vehicle is driven and how old the vehicle is, the unitized bearings may need a little persuasion with a soft-faced hammer to facilitate their removal from the hub. 4

7 6 7 Use care when removing the unitized hub assembly from the halfshaft. Don t let the halfshaft hang incorrectly or damage may occur to the seal area. 8 Note that this particular halfshaft unitized bearing assembly has a spacer installed on it from the factory. If you buy a quality replacement part, this spacer is reused. Some lower-priced aftermarket versions may be made differently and it s anyone s guess what happens in regard to the spacer s usage. 9 Note the amount of particles on the backside of this huband-bearing assembly. Where do these particles come from? Residue from normal brake wear, along with road debris and anything that is magnetic, can be attracted to this area that is partially exposed on the backside of the hub assembly. This particular hub assembly is simply being cleaned, as there were no mechanical problems with the bearing assembly, by first wiping the unit down with a rag. 10 The exterior of the bearing assembly was then cleaned with a sprayon brake cleaner to remove any remaining petroleum film and allow the area to be properly degreased in addition to being cleaned. 11 The unitized hub-and-bearing assembly received a light layer of lubrication where it slips into the knuckle assembly. This facilitates easier installation. 5

8 phototech After the hub-and-bearing was reassembled, a diagnostics of the wheel-speed sensor is performed by first locating the connection where the wheel-speed sensor plugs into the body wiring harness. 15 The connection is secured not only in a clip-in manner, but with an additional interlock device that must be partially removed in order to separate the connection. 16 The easiest way to do an output-sensor diagnostics is with a lab scope. The connection shown allows the lab scope to be connected while the wheel-speed sensor is connected as part of the circuit. Otherwise, there is no output from the wheel-speed sensor. 17 Locate the correct connections and, according to the wire color of the test leads, plug it into the wheel-speed sensor on one side and the bodywiring loom on the other side. 18 The completed connection is shown. With the scope hooked up in this manner you can perform an output test with the key on by rotating the unitized hub-and-bearing assembly to produce output from the wheel-speed sensor. The wheel-speed sensor pattern can then be analyzed and recorded on the scope pattern. In the case of this vehicle, a normal square-wave signal was shown and the rest of the vehicle was assembled and test-driven after the code was cleared. No additional problems were present on the vehicle. 6 The extra connections on the test lead are being tied into the oscilloscope. If a code on a vehicle indicates a wheelspeed sensor fault and it is traced to a magnetic buildup, don t just clean off the magnetic particles and assume that the vehicle is OK. Perform an output test using a lab scope or a scope meter. This assures you that the output is correct and that you have truly cured the problem. Is this a simple repair? Yes. What is the total working time? Less than an hour. The total vehicle labor charge includes diagnostics, repair and confirmation of the repair. This is a job that solved a real problem for a customer and assured that his vehicle went out correctly fixed and will stay out. Special thanks to Assistant Professor Alexander Richards and his students at the Automotive Technology Management department at University of Central Missouri in Warrensburg

9 phototechby Ron Henningsen Undercar Digest Technical Editor Bench Bleeding & Pressure Testing Master Cylinders Bench bleeding a master cylinder should be a simple procedure that removes all the air from the master cylinder, fills it with fluid and allows you to install a master cylinder with a rock-solid pedal, as there is nothing but fluid in the system. Unfortunately, this isn t always the case. The following photos will show the simple procedures for bench bleeding and how to properly pressure test a master cylinder. Note: It should take longer to find the correct master cylinder plugs than to bench bleed the master cylinder. It is a quick, easy and accurate way of making sure that the master cylinder is establishing pressure. If it is establishing pressure on the bench, it will establish pressure when it is on the vehicle, provided the push rod length booster is working correctly. For pressure testing, the master cylinder kit shown in Photo 15 is available through a wide range of various tool distributors. The tool between the two gauges is an old Teves 2 accumulator pressure adapter that hasn t been used for years, but is still included in the kit. Throw it into the scrap heap. No one uses them anymore. The various adapters shown all come with the kit. If you don t have the right adapters it is easy to find the oddball that may not be included. The following procedure is designed to aid in making you a true professional brake technician. 1 Remove the cap, whether it is a snap-on cap like this one or a twist-on cap. 2 3 If a snap-on cap doesn t come off because it is slightly stuck, don t use a screwdriver to pry from the bottom up. Tap the top of the cap with a soft mallet or the handle of a screwdriver and it will usually snap free. Doesn t everyone have a can of bench bleed plugs? You should. I have accumulated a supply of various plugs over many years. I ve never thrown away a screwin master-cylinder plug of any type. 4 This style of plug was originally designed for a loop type of bleeding system. It now has a plug put into the end of it and has become a master cylinder bench bleeding plug. 7

10 5 8 Place whatever plug fits correctly into the master cylinder and tighten it slightly with a wrench. These happen to be plastic plugs so don t over-tighten them. They will do a good job of sealing fluid. 6 You can see the primary side of the master cylinder is beyond the compensating port and the second area is going just beyond the port because air is still rising. 9 Fill the master cylinder to its proper level with the proper type of fresh, clean brake fluid. 7 At this point, note the stroke of the screwdriver or whatever tool you are pushing by simply putting your finger on the tool at that point and letting the master cylinder pistons return. 10 Start stroking the system. At this point you are not really bleeding, but just trying to get the air out of the bore of the master cylinder. Stroke far enough to get the piston cups by both compensating ports. With a marker pen or tape, mark the stroke length of the screwdriver. This is how far you will stroke the system during bleeding. It is not necessary to stroke any farther than this. Doing so can cause problems by actually nicking a cup on the stop screw. 8

11 phototech Start bench bleeding the master cylinder. With the plugs in and the stroke length determined, repeatedly stroke the master cylinder primary piston, which will then move the secondary piston. Do this until there is no longer any air coming up from the compensating port. This usually takes strokes to achieve. 13 Use a ball peen hammer to gently tap the bottom of the master cylinder along the entire length of the cylinder bar. When you do this, note the amount of air coming out of the compensating port. These are small air pockets that are attached to the cups, springs and other components of the system. Do this three or four times, stroke it a few times and repeat until no air comes out. 14 Another way to bench bleed a master cylinder or at least begin to bench bleed one is to use a reverse fluid-injection bleeder with a rubber tapered tip. Fill the master cylinder through the outlet ports. This forces most of the air in the system up through the compensating ports and into the reservoir. After filling each half, put plugs in it, continue tapping it and stroking it. This will slightly speed up the process. 15 This is the old tried-and-untrue (in my opinion) method of bench bleeding a master cylinder. It is very difficult to get all of the air out as the air just constantly loops back and forth in the tubes to the reservoir so the tubes are in the fluid. This way never did work, never will work and is not something I would ever do unless no plugs are available. To pressure test a master cylinder you need a set of brake pressure gauges. Don t try to adapt a set of gauges that are not made for this purpose. They don t work. 9

12 phototech Don t think that you can get a reading by stroking it with a screwdriver or any other tool. You must set up a tool that is really a puller as shown. Anything else will not control the stroke and will not provide accurate readings. 18 It is very important to have a gauge with the ability to bleed the air out of the hose. If you don t, don t bother pressure testing as you are just compressing air, resulting in an inaccurate reading. With the gauge hooked up, depress the master cylinder slightly, open up the bleeder valve until fluid runs out and close the bleeder valve. You will then have a solid column of fluid and an accurate pressure reading. With the tool set up you can tighten the center screw to measure the amount of stroke movement. If you are comparing master cylinders for pressure output, stroke length, etc., this is a handy way to get accurate data If you get bubbles from the compensating port when you stroke it as shown in Photo 18, you haven t correctly bench bled the master cylinder. Stop what you are doing, get the air out of the system and then pressure test the master cylinder. 10 By having gauges hooked up on both the primary and secondary side of the master cylinder, you will be able to tell what the initial pressure is, what the stroke length is and whether both halves are putting out equal pressure. It is an accurate way of determining whether the master cylinder is generating pressure. If you have pressure under this test, you ll have pressure when it is in the car. If you don t have pressure at the wheels, the problem is elsewhere, not in the master cylinder.

13 phototech When you apply the brakes of a vehicle, no matter what it is, if the pedal pulsates up and down you probably have a thickness variation of the rotor. As the pads follow this thickness variation the pedal pulsates up and down. Shaking Brake Pedals By Ron Henningsen Undercar Digest Technical Editor Never heard of a shaking brake pedal? Don t believe it exists? How about warped rotors? You ve heard of them, but they don t actually exist either. The fact is that if you have a brake pedal that pulsates up and down when you apply the brakes you probably have a rotor-runout issue caused by thickness variation. This is usually caused by rust and scale buildup between the slip-on rotor and the hub face or a bad-bearing assembly that causes the bearing hub face to have runout. In any case, please remember if people can believe in work orders, I can make up the term shaking brake pedal. The following photos will show you how to diagnose, cure and prevent a pulsating brake pedal from occurring. Many technicians believe that whenever they have a brake-pedal pulsation problem they can slap on a new rotor and let the vehicle go, only to have the problem reappear in a short period of time. Hub faces must be cleaned and they must be within runout specifications. You are kidding yourself if you think you can just slap on a new rotor. Most problems, when it comes to pedal pulsation, are basic in nature. Spending a little time to look at, diagnose and correctly repair the vehicle will go a long way toward assuring your customer of the high level of professional service he assumes you always provide. On this vehicle the runout of the rotor was enough that the pads rubbed against the rotor in one spot, wearing the rotor thinner. The resulting shiny spot can be seen at the 12 o clock position. When the brakes were applied, once every cycle of the rotor you could feel the pedal go up and down. 3 To determine whether you have rotor runout, clamp the rotor onto the hub by using lug nuts and a proper adapter, put a dial indicator on it, mark the location and spin the rotor. 4 The adapters shown are the second most accurate way of properly clamping a rotor onto the hub face and a method that works well. 11 After using the correct adapters, hook up a dial indicator and mark a reference point so that you know when you have made a complete revolution. Make one revolution and determine the amount of runout. This is done after zeroing the dial indicator at its base reference point. 6 If you use adapters such as washers or rotate a lug by putting the lug nut on backwards, you will probably have some induced runout error. If you don t use the right adapters, don t bother taking runout. You won t be accurate. 7 This is what happens to a hub face in many parts of the country. Rust and scale builds up on the raw steel hub face and causes rust jacking, forcing the rotor to have an unequal amount of runout. 8 This shows one of the most common methods used by brake technicians of cleaning rotor hub faces. Many technicians put this tool in their drills, spin it until a circle is polished, possibly clean up between the lug nuts and let it go.

14 This is why you can t just let it go. You can have rust and scale buildup on the hub face that a tool will not remove. This type of buildup must be removed with a hammer and chisel or a descaling tool. 10 If runout on a hub is bad enough you ll do what is shown in this photo. A hub is being replaced. If you have a bad bearing or if you have any type of impact damage that has caused excessive runout to the hub face, replacement is the only solution. You can sit there all day long looking at it and hoping that it will go away, but if you have excessive runout on the hub face the hub must be replaced. 14 This is another excellent use of sprayon brake silencing material. This compound gets into all the nooks, crannies and crevices and coats the inner rotor hat. It really does prevent rust and scale buildup. 17 This is the amount of rust and scale buildup that the hub-cleaning tool in Photo 8 won t remove. It was removed by just tapping it with a small chisel and ball peen hammer. This amount of buildup would easily have caused runout, even on a new rotor when it was replaced. 11 Clean the inside of the rotor hat but not to the point that sparks fly. Clean up the rust and scale down to the bare metal but don t do any sanding as this will cause the opposite of rust and scale buildup. 15 Using an on-car lathe to turn a rotor to compensate for runout is an excellent idea and works very well, but even on-car brake-lathe manufacturers don t say that you can turn a rotor without inspecting for rust and scale behind it. 18 The sanding of hub faces can really be questioned. Sanding until sparks fly means that you are removing metal. Just the opposite of buildup, this too can lead to runout, as well as pedal pulsation-induced error. 12 Many technicians like to coat the hub face to prevent future rust and scale buildup. This is fine, but you don t need the amount of lubrication shown. In addition, the type of lubrication used isn t as important as the fact that it clings to the bare metal, coats it and prevents rust and scale buildup. If you are not taking runout on a hub face, prepare yourself for some frustration. It is somewhat difficult to get the dial indicator into position and clear of the studs, so if you have the dial indicator remain on the outward-most part of the hub, there is usually a rust or scale buildup in that area. It s something of a darned if you do, darned if you don t situation. Try to take hub runout on hubs that have studs pressed into them. This is the proper way to perform an on-car brake-lathe operation. Remove the rotor from the vehicle, check for rust and scale, and clean up the hub face and inside the rotor as necessary. 19 Perform runout to see if there is any excess runout specification for the vehicle. If it is beyond specification, determine why. An on-car brake lathe will solve many problems but it cannot make good parts out of bad parts. If you have a base-reference problem you will not be able to permanently solve the problem by simply using an on-car brake lathe. It is an excellent tool that does an excellent job but it cannot make magic of parts that are bad. 12

15 Braking & Shaking: Are You Sure You Know the Cause? By Dann Ingebritson With 45% of technicians being older than age 44, the average technician has more than 25 years experience, many of those years doing brake service. In fact, if that technician averaged four brake jobs a week, they performed more than 5,000 brake jobs so far in their career. So, when a seasoned technician calls us on our brake hot line, we assume they have tried everything they have learned over the years. This week I took a call from one of those average-aged technicians concerning a vibration/noise/ shake issue on a 2010 Chevy My first thought was the typical problem of excessive rotor runout. Too much runout causes pad-torotor contact every revolution, (Figure 1) even when not braking. The resulting thickness variation is what causes the pedal to pulsate up and down. But after talking with this technician, that was not the case. He knew all about runout issues, had already installed new rotors and even checked the runout with a dial indicator (Figure 2). 1 His problem seemed to get worse 2 after he installed front pads and rotors so naturally he figured it was the parts. The customer did mention the slight shake and vibration when he brought the truck in for original repairs, but the technician figured all would be fixed with a professional brake job. So, all parts were replaced again, this time with different flavor brake pads. But he had the same results. Machining rotors with an onthe-car lathe followed along with balancing all tires the same vibration was felt. This is where the shop started calling around to friends, other shops and finally our tech line. As I stated earlier, this shop did a professional brake job twice now with basically the same results. We discussed swapping tires and wheels from a similar truck so he tried that, no help. I started doing research online and with my contacts and came up with a lot more repairs than I ever imagined. I ll discuss them in order of popularity starting with the driveshaft. I know what you re thinking: Brake vibration cannot be caused by an out-of-balanced driveshaft, but I had some real good technicians swear they fixed it that way. I ll explain my theory after I list a few more fixes. Reading through some chat lines I saw a few repairs that included changing the pinion angle either by shimming the differential or the transfer case. One technician I used to work with at a local GM dealer guaranteed me it was in the ring and pinion. Some mentioned body mounts and one said definitely the transfer-case mount was 13

16 4 compressed. Another chat line 3 said adding a steering damper normally corrected the vibration. The same group talked about road force balancing. Another popular fix was adding 500 pounds of weight in the bed. Most complaints did mention the problem was more evident when the truck was unloaded. Remember the original complaint? Noise/vibration when braking. So which repair is correct? They all may be. GM does seem to have an issue with the Silverado models due to the amount of discussion on the web but it may be a combination of things causing the perfect storm. Some owners said the issue started around 10,000 miles, some at 50,000 miles. My neighbor has the same truck and never had an issue. I do believe drivetrain alignment is an underlying problem that is exaggerated when braking. Braking causes the front nose to dive (Figure 3), rear shocks to extend, especially with miles on them, which in turn changes the drivetrain angle. Many of the fixes include correcting or changing that angle. Many owners of lifted fourwheelers (Figure 4) just put up with a little vibration and shudder because of the extreme changes they did to their trucks. People who have stock trucks expect a lot more from their vehicles. In fact, the old saying, This thing drives like a truck, is not used any longer because our trucks ride like cars in most cases. Another point to consider is alignment angles change when the vehicle nosedives. All angles, including steering-axle inclination (SAI), are affected when ride height changes. You may have to think outside the box to repair your individual problem. Getting back to our problem truck, the new brake parts up front possibly just restored the braking system to original and allowed the fronts to work normal again. This, in addition to worn shocks, springs, bushings, mounts, U-joints and even steering parts, all contributed to the problem. What I m getting at is not all problems fall in line with past repairs. I recall working at a GM dealer years ago, instantly diagnosing a vehicle after reading the work order. We did the same repair to some platforms so many times that you skipped all diagnostics and went right to the common repair. That sometimes backfired on you and then you had some explaining to do to the service manager. The technicians that guaranteed their repair was correct in the chat lines were not always correct. The fact that there were many fixes for the same basic problem proves that. So what fixed our subject truck? So far a rebalanced driveshaft with new U- joints, a transfer-case tailshaft bushing and a rear transmission mount did the trick. They are going to replace the rear shocks too. Braking from any speed is great. The customer is happy the truck is fixed, but not happy spending the extra money. Moral of the story? You are never seasoned enough to know everything. That s what makes this career challenging. 14

17 Technicallyspeaking Brake Quality & Codes Are Important By Ron Henningsen Undercar Digest Technical Editor Figure 1 The belief that the purpose of doing brake repair is to restore a vehicle to like-new performance is not just an idle statement. Professional brake technicians, repair shops and people who truly care about professional service and vehicle safety use quality brake materials. This article will address a couple of specific areas where the quality of the manufacturing process and materials make a major difference. One such area that is not often understood is the metal backing of disc-brake pads. If cheap steel or a type of steel is used that does not have anti-corrosive properties or that has scaling issues because of its manufacturing process, disc-brake pad-separation problems can occur. In these instances, rust and scale builds up or the scale itself flakes and scales causing the bonding to separate between the brake pad and the steel backing (Figure 1). A second area of concern is the type of steel and the stamping process, along with correct dimensioning of the pad ears. If any of the procedures vary from the OE requirements, problems with the pads sliding correctly, rust and scale buildup and other conditions that can inhibit efficient operation of the brake may occur. The method of attaching friction material to the backing plate should also be considered. If OE uses a certain method the aftermarket logically should follow, as there must be a reason for it. There are many different ways of bonding or attaching bonded friction to the backing plates. The technician really has no way of knowing what he is getting in the box. In the automotive aftermarket, white-box wagon jobbers or wagon vendors often visit shops with deals on friction material for the most popular vehicles. They offer some of this product at a ridiculously low price that seems attractive to making the shop more profitable because the customer doesn t pay any less, only the shop does. Without knowing the type of steel, the bonding method and the type of friction, this could be a situation of if it sounds too good to be true, it probably is. There is nothing wrong with buying brake friction at a good price, provided the quality, specifications and all other parts are equal to what came on the vehicle and fulfill the requirement of allowing the vehicle to stop in a name-brand friction or supposed name-brand friction being offered to you at a ridiculously low price by someone you don t know who just walks in your door. Counterfeit brake products are still sold in this country and are virtually untraceable once a shop buys them. Stop and think. What are you buying and why are you buying it? It s a lot like the case of a guy walking down the street who has a truck with a bunch of coolers on the back selling shrimp from Louisiana for a deal, as he just happened to be driving through your state. This is a bit of a stretch if you re from the northern part of the U.S. This gentleman probably spent $20 or more driving to where you are and just happens to offer you this deal. Again, if it s too good to be true, it probably is. Quality friction pertains to friction that is in compliance for the removal of copper. In the very near future, copper must be less than half a percent by weight. There are laws in California and Washington state that are being adapted nationwide and will mandate this re- 15

18 quirement. In the near future, how do you know if your brake friction is complying with the law? First, there is a phase-in period of time that will allow for present inventory to be sold. Second, the new friction products that are being formulated and used by major manufacturers, even at this time, contain a designation on the edge code that alerts you to the percentage of copper and other requirements. What you want to look for is the leaf design on the box. Three designs discussed below indicate the percentage of copper and other materials. The three darkened leaves, marked as N design, indicate that the friction material contains less than half a percent of copper by weight, asbestos-formed fibers of less than one-tenth of a percent by weight and cadmium and its compounds less than 0.01% by weight, along with other specific requirements of various other materials in the compounds (Figure 2). Two darkened leaves or B design contains between half a percent and 5% of copper by weight, along with other requirements. Figure 2 One darkened leaf or A design with two other lighter leaves represents asbestos formed fibers by weight. In the future you will want to be aware of the rules and requirements as well as the packaging. If you get a box of new-formulation friction and it has the three darkened leaves on it, you know you are in compliance. In the states of Washington and California there will be substantial penalties if you sell the wrong type of friction after a certain date. Whose job is it to make certain that the friction in the box matches the labeling? If you buy from a major manufacturer and you buy friction in a sealed box with the designation printed on the outside, you will have some level of assurance that you have done your job. The friction manufacturers would not violate the specifications in their designations. They all belong to a group that accepts voluntary certification for the removal of copper and other materials. Why buy quality friction material? First, it s the right thing to do. Second, it s morally the right thing to do. Third, it s ecologically the right thing to do. Last, but not least, it will assure your customer of a brake repair on his vehicle that will return its stopping power to the level that assures safe driving and vehicle operation. Why would you put any friction on a vehicle that would not comply with the rules, regulations and laws for a safe environment and enable your customer to drive with the assurance that he can stop his vehicle according to how it was designed to be stopped? Seldom, if ever, are brake pads removed from a vehicle and examined to determine if they were the cause of an accident. When you see a car stop on the highway by slamming on its brakes after a long line of vehicles in front have stopped and the driver wasn t paying attention, is it the right day for the friction? Will it dissipate the heat correctly? Does it have the right coefficient of friction for stopping? Is rust jacking between the pad and the backing plate increasing the effective stopping distance? All of these things are important. You do the type of service you do because you care and because you are professional, not because you want to buy the cheapest friction you can find, charge the most money possible for it and think only about your bottom line. Courtesy of Akebono 16

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20 Solutions developed for OEMs drive high-quality aftermarket manufacturing When it comes to installing one of the most critical automotive replacement parts brake pads choosing the high-quality, high-integrity products that OEMs trust and demand should be an apparent choice. Akebono Brake Corporation, the leader in ceramic brake technology, is one of the few manufacturers to fully develop, test and validate its aftermarket products based on years of engineering and manufacturing brakes for OEM applications. As a result of this extensive experience, Akebono has fine-tuned its brake pads to virtually eliminate brake noise and dust without compromising friction and brake integrity. No matter which Akebono product you re buying or installing, you can trust you re always getting the best braking solution for your vehicle. Experts warn installers to be wary of other brake pad products on the market. Don t be fooled by cheaper, high-volume brake pad manufacturers that market fancy slots or flashy packaging, said Ken Selinger, Director of Sales and Marketing, Akebono Brake Corporation. Akebono has perfected and fine-tuned the most important attributes the ones you don t see. One of those attributes is brake pad porosity, which, although invisible to the naked eye, contributes significantly to reducing brake noise and fade. Akebono has engineered the perfect balance of porosity, precisely crafted to provide the highest friction and lowest noise. Akebono s Pro-ACT, EURO and Performance Ultra-Premium ceramic brake pads are designed with the highest precision to offer our customers unmatched braking power and quality, explains Selinger. For added integrity, Akebono applies a phosphate treatment and a proprietary, advanced technology powder adhesive to its pressure plates, which helps to improve the bond between the friction material and pressure plates. Not all brake pad suppliers can make this claim. Choose brake pads from the experts the OEMs turn to and trust for superior braking, Akebono Ultra-Premium ceramic brakes. Akebono is proud to manufacture 100 percent of its Pro-ACT, EURO and Performance Ultra-Premium aftermarket brake pads in the United States. To learn more, visit akebonobrakes.com.

21 Technicallyspeaking Selecting Training for Your Shop By Ron Henningsen Undercar Digest Technical Editor When selecting training for your shop, first decide why you are having your employees participate in a training class. Is it to handle a present problem in your shop? Is it to update training to maintain efficiency? Is it to update the training of an employee with limited skills so that he might advance to more complex jobs? What is the overall goal and objective? It s not just to spend money and have your employees absent from your facility for a period of time. Some shops believe that fellow employees in the shop should handle training. This is a noble goal, but it is not necessarily the most efficient way to use your training dollars. You should do it only after careful consideration. If you have some very high-level technicians in your shop you may wish to allow them to go to training sessions that occur outside or even during normal working hours in order to advance their skills and enable them to per- form work in your shop more effectively, increasing your level of efficiency and profitability as well as their own. In addition, a general-service area class offered in the evening at one of the local parts supply houses may be something that benefits everyone in the shop from the most-certified master to the person who sweeps the shop floor. Everyone gains from knowing the latest rules, regulations and procedures on vehicles. For many years, there was much discussion about whether technicians should be paid for attending training. In today s marketplace, and with all the various state and federal regulatory agencies, you might wish to check with your accountant, attorney or some other person who handles your HR duties whether you can insist upon employees training on their own time without pay. The purpose of this article is not to reignite the discussion, but to be aware that situations may occur. Some technicians will attend any and all training sessions, including online training, that is offered to them, whereas others prefer to look at a training video playing on an overhead television screen in the lunchroom while they are on their lunch break. Be aware that not only do technicians have different degrees of interest in participating in training, but they also have different learning styles. Some technicians can learn from the Internet as well as at 19

22 various professional and amateur training information presentations, whereas others require a textbook, a structured paper, study guides and/or virtually hands-on practice demonstrations in order to acquire a skill. Everyone is different. Facilitate the differences in people in your shop with different training methods, if necessary. Manufacturers today may be offering fewer evening training sessions than they did many years ago, but what many manufacturers are offering today is training sessions of one-three day training sessions at multiple locations across the country. Even though you may not reside or operate in a major metropolitan area, there may be more training sites today than ever before where professional training is offered. Federal-Mogul Motorparts, for example, has opened a multitude of sites, along with a training-van program that enables training to essentially be mobile. Check this out through your parts supplier and various brands of parts that you buy to see what is available. Other manufacturers may only have one or two training sites nationally, but these training sites rival OEs in terms of the skill level of the trainers and the subject areas they train in. Training at these sites is at various skill levels within the subject areas. Find out not only what the training subject area is, but for what technician skill level the training is designed. For a master technician, basic or intermediatelevel training could be a waste of his time and result in boredom and disinterest, but sending an introductory-level employee to an advanced training session in any subject might be overwhelming and prevent even the most basic of learning because of his apprehension in trying to keep up. When someone walks into your place of business and says that he is offering training or there is training available offsite or even in another city or state, don t just take the piece of paper, file it next to the cash register or telephone and figure you ll get to it later. Develop a training file. Drop all training information and references into this file and at least once every other week go through the file to find out what s coming down the pipeline, what s available and what level of training is being offered. I know many technicians who have younger families whose wives work and who have to coordinate their schedules around family functions and spouses work schedules. This means that in many cases their ability to participate in any training outside of work hours is virtually non-existent. For this reason, many training providers have gone to online training programs supporting hands-on training. This is perhaps the most practical method of receiving training today, as it enables technicians to stay home, maintain their family schedule and still find a few hours every week to participate in some updating or advanced-level training. The real answer to the question of what to watch for when selecting training is what to watch for that will make your shop, your employees, your customers and your overall business efficiency the most effective. There is no one answer for everyone, even within the shop. A training provider should perhaps be judged by the same criteria that your parts supplier is judged by. Who will support you and your business, giving you service and handling any problems? Who s the source of knowledge and has the latest in updated information and all other aspects of your business? If you look for the same qualifications in your training supplier that you do in your parts supplier, you may find an efficient and effective answer to that question. 20

23 Technicallyspeaking Irregular & Unusual Pad Wear By Ron Henningsen Undercar Digest The reasons for irregular pad wear relate to any of three major problem areas. The product itself may be the cause. A second possibility involves the failure of individual mechanical brake components and may include installation and technician error when installing the pads. The third area is centered on an attitude of What irregular pad wear? I never see it in my shop. In discussing these three areas, let s begin with the last one. In many shops, when preparing to do a brake job after an inspection or a determination of need, technicians simply whip off the old brake material, see how far they can pitch it toward a trash can and move on with the repair function without analyzing or reading the old brake pad. When you take brakes apart, the old brakes will tell you a story. Take a moment to look at them and figure out what was going on, even if you only figure out that everything was working correctly. The second area of unusual pad wear relates to substandard product manufacture because of accidental manufacturing issues or because a product is cheaply made or made by a manufacturer with little care or concern for the overall safety or quality of the product. Delamination of friction material from the disc brake backing is becoming more prevalent and is usually traced to the fact that the type of metal used is not of the quality of OE or what it should be. The metal rust or scale builds up and delaminates the pad or leads to a rust-jacking issue that causes the pad to start separating from the metal backing. This is almost always a manufacturing problem with very few exceptions. Other considerations include the accuracy of the metal stamping on the ears, whether the friction material has been accurately placed in the right location on the metal backing, the straightness of the pads and the proper attachment of external hardware such as wear indicators with devices. In addition, the type of metal backing, along with the type of pad, can have a resonance issue that leads to a noise problem. In the case of rapid pad wear-out, if the friction is not the proper type or of the proper quality, no matter how accurate the brake balance, brake-distribution forces, etc. are in the vehicle, the pads will exhibit rapid wear. Using improper material can cause rotors to wear excessively rather than maintain the pad-rotor wear balance designed into the vehicle. In the area of technician-induced unusual pad wear or wear problems, the following can happen. A lack of stopping power can result if, when the rotor is turned, the correct micro-finish is not applied and the rotor is not properly cleaned after turning by washing with soap and water followed by a brake-cleaner This tapered pad wear was caused by a pad-tocaliper contact problem. The pad was not allowed to slide in and out correctly and bound on one end in an applied state, causing the wear problem. product, if brake bits are dull, etc. These can all cause problems ranging from brake noise to a lack of stopping power and wear-out problems. Another issue that has become prevalent over the years is tapered pad wear. Although tapered pad wear in a fore-and-aft manner in which either the leading or trailing edge of the pad wears before the other is 99.9% of the time caused 21

24 Note that this pad only had pressure applied on one half of the metal backing. You can see the contact area of the pad backing to the caliper-piston-face contact marks. by a caliper slide-related issue, it should be noted that it is also possible to have top-to-bottom pad wear caused by an overheating issue in which the system warps and one part of the pad receives more pressure than the other. That type of pad wear is easily identified by the cracking, glazing or other conditions of the pad. Additional unusual pad wear problems can occur because the metal ears of the pad are not lubricated where they fit into the caliper-mounting bracket. This can cause restricted movement or metal fretting or dimpling of the bracket. The pad may move on one side but not on the other, leading to unusual wear patterns, not the least of which is a potential tapered-wear issue. It is somewhat amusing to hear a shop say that the outer pad on the right-hand side is continually wearing out prematurely, in an unusual manner or whatever. This is giving the manufacturer of the brake pads way too much credit. Who in his right mind would think that the manufacturer of a brake pad could batch up friction material, make sure it s installed just in the outer pad of a vehicle and then make sure that it s installed in the outer pad that ends up on the right-hand side of any specific vehicle and have the problem more than once? It s not a manufacturing problem when the same pad on the same side, whether inboard or outboard, wears out more than once. There have been situations of pads wearing in an unusual manner because of a design issue such as on some of the GM vehicles over the years where the outer part of the discbrake pad doesn t come in contact with the rotor and therefore does not wear out until 98% of the pad is worn. The 2% on the outer edge that has never contacted the rotor is not worn. This has nothing to do with the quality of the friction material or the technician. It is a case of the pad not hitting the rotor completely. Remember that pads wear according to how they come in contact with the rotor. If they don t squarely come in contact with the rotor or with equal pressure, they won t wear square and flat. If you think that pads are hitting the rotor or contacting the rotor squarely, think about this parallel situation. When you sharpen a chisel, either a metal chisel from your toolbox or a wood chisel, on a sanding belt, blacken the tip of the chisel with a black marker and then as carefully as you can put the chisel blade up against the sanding belt with the belt rotating in the right direction for how you are placing the chisel. Touch it lightly and as squarely as possible and then pull it away. When you look at the area of contact you may be surprised to find that there was not full contact of the chisel tip regardless of how careful you were. 22 This pad separated from the metal backing and is the same pad with the taper-wear problem. This condition simply amounted to a situation where the intitial application of the pad to the rotor didn t cause any friction on that end of the pad. The same is true with brake pads. Visually they may appear to be contacting the rotor in a flat, even and equal-pressure manner, but they may not be. Read the story the pads tell you when you take the brakes apart and when you have unusual wear, determine by visualizing in your mind what the wear pattern is and what could have caused it. Once you have determined the true cause of the situation, fix it while you are servicing it, replacing parts as necessary, and return a vehicle to the customer that meets the end objective we all should be working for, like-new braking performance.

25 As seen in Brake Tech/Talk Some F-150s don t want to pass shiny objects! You may not be old enough to remember Not the Figure 1 year, the film ( 2001: A Space Odyssey ). Sorry to start with another show-biz reference, but it seems to fit: In 1968 director Stanley Kubrick and futurist/novelist Arthur C. Clarke teamed up to tell the thoughtprovoking story of a journey into outer space in which (among other things) a renegade computer, the all-seeing HAL 9000* (Figure 1), decided it knew better than Dave Bowman (not the Fram Racing/Shadetree Mechanic guy, the astronaut character played by Keir Dullea) and took control of the mission. So much for most of the humans on board! The future portrayed was scary, to say the least, and although the predicted year has come and gone, some of what Clarke and Kubrick foretold appears as if it may yet, in some form, come to pass. Certainly there are now instances in which drivers find their vehicles making judgments on their own and they may not always agree with the decisions the car or truck may make. And that brings us to this month s Service Alert: Should drivers of certain 2015 Ford F-150s (Figure 2) come to pass a highly reflective semi-trailer and the pickup s adaptive cruise control is engaged, the 150 may decide to apply its brakes. (Drivers who name vehicles may consider HAL for these pickups!) Problem identified: Optional adaptive cruise control (Figure 3) on certain 2015 Ford F-150 pickups may apply the brakes inappropriately. This could happen while passing highly reflective, large moving objects such as certain Class 8 trailers. While this is taking place the collision warning system red light may illuminate. Ford points out that the driver may override the adaptive cruise control at any time by applying either the accelerator or brake pedal or by pressing the cruise cancel switch on the steering wheel. There is, of course, a chance of being hit from behind when a trailing vehicle sees nothing ahead of a pickup that begins braking for no apparent reason. Vehicles affected: Up to 36, Ford F-150s built at Dearborn Truck Plant, March 18, 2014, through Aug. 5, 2015, and at Kansas City Assembly Plant, Aug. 11, 2014, through Aug. 6, Campaign number: 15V614 (NHTSA) Repair procedure: Dealers will reprogram the trucks adaptive cruise control modules with updated radar software, free of charge. The recall was set to have begun on Oct. 19. Additional information: F-150s with conventional cruise control are not affected; neither are trucks without cruise control. And if the driver never turns on the accessory and just works the gas and brake pedals him/herself, then they shouldn t encounter the issue, either! As NHTSA dryly points out, A vehicle that unexpectedly brakes increases the risk of a crash. Ford reports at least one accident that may have resulted from the condition, without personal injury. (*HAL was said to stand for Heuristically Programmed Algorithmic computer but in reality the letters just come right before I, B and M in the alphabet.) Figure 3 Figure 2 23

26 As seen in Brake Tech/Talk Electronic parking brakes: Nothing new anymore! 24 Maybe the electronic parking brake (EPB) seems like high-tech complicating something simple that we already understand at first blush, at any rate. But actually, in some ways EPBs simplify things: A bunch of cables and a lever/pedal are replaced with a switch, some programming, wiring and actuators. And, in case you haven t noticed, there s already plenty of wiring and processors in modern cars! This, in fact, makes it relatively simple for a manufacturer that has already effectively encircled a car or truck with Controller Area Network (CAN) wiring to use some of the existing circuitry to control an electronic parking brake as well. Also, according to vehicle-component and system suppliers, they can be used in conjunction with other systems, like stability control, without having to involve hydraulics. There s also some discussion of incorporating EPBs in genuinely redundant emergency brake systems. In the case of total hydraulic failure, the circuitry and electric actuators could be used to apply the parking brakes. Such systems would also monitor application to prevent the skids that can be caused by rear-wheel lockup, which inevitably occurs when a panicked driver yanks a parking-brake handle that works only the rear-wheel brakes. EPBs also make life less challenging for vehicle interior designers, because it s easier to find a place for a switch than for a lever or a handle, as seen in this shot of the console in a 2011 Jaguar XKR (Figure 4). The downside for drivers is that if they re new to a vehicle that someone else has parked, they may have to search for the switch before they can release the brake and drive off. Then again, that s not always a problem: Many EPB systems are programmed, as is this Jag s, to self-release when the shifter s been moved from park to drive (or Reverse) and the throttleposition sensor signals that the accelerator has been applied. These systems even give manufacturers the opportunity to inject some of their own personalities into the mix. For example, recent EPB-equipped Volvos will self-release in drive or reverse, but only if the driver s seatbelt is latched. If the belt s not fastened, the driver has to release the switch manually. Volvo s big on safety, after all. But even if there s no automatic release, EPB operation is relatively uncomplicated: The driver pushes or pulls a console- or dash-mounted button, sending a signal, via the car s CAN bus, to the EPB module. The module then sends current (typically 12 volts), via dedicated wires, to the actuators on the calipers (Figure 5). Each actuator con- Figure 4 sists of a motor and gearbox, driving a shaft threaded into a spindle. Depending on which direction the motor is turning (based on the polarity of current feed) the shaft/spindle assembly either expands, pushing out the piston and applying the brake, or retracts, releasing it. Some vehicles use just one motor, with conventional cables running to the parking brakes at each rear wheel. That s fine. But what about when things go wrong? Are you going to need to cough up big bucks for costly, new tools in order to service these new systems? Not really. You ll need the same modern tools you need for many other servicing procedures today. Servicing matters EPBs can affect routine servicing because, for example, you need to retract the caliper pistons when replacing pads. That, of course, is nothing new. But unlike the pistons you re used to encountering, you can t drive these in with a piston retractor or C-clamp, or retract them by screwing them in. The prescribed method is to use a bidirectional scan tool that communicates with the car to command the pistons to retract. That s fine if you have the right scanner, but if you don t, everything can come to a halt. One technician we know, who planned to do a routine pad replacement on a late-model Audi, went Uh-oh! when he had the car in the air, wheels-off. That s when he realized it had electronic parking-brake motors on the rear calipers. He was swapping the pads as a favor to a friend and though he had a scan tool it wasn t one that spoke Audi. Fortunately, he s resourceful and had a key kernel of information: His online manual verified that the parking-brake motors on this car operated on 12 volts. So he disconnected the harness from the actuator assembly, lugged over a battery and commanded the pistons to retract by applying power directly. In this case, it worked fine. This shouldn t be your standard operating procedure for installing pads in EPB-equipped vehicles, and the technician we interviewed doesn t plan on servicing any more Audis with them until he buys the right scan tool. But his story illustrates two major points: 1) New technologies even simple ones present new challenges. 2) When a smart technician understands how a system works, he can often come up with a way to work around any new challenges it presents. Figure 5

27 As seen in Brake Tech/Talk Tips for preventing fast brake-pad wear in hard-working GM/Ram trucks Many trucks on the road today belong to hobbyists, Figure 4 campers and homeowners and will never see commercial service. But others have to work for a living, carrying big loads and/or towing heavy trailers. (Come to think of it, some campers drag some pretty large trailers (Figure 4). While it may be a cause for concern when a gentleman Courtesy of Little Island trucker s brakes wear quickly, hardly anyone may think it unusual for a work truck to go through wear parts (pads, rotors, shoes, drums) in relatively short order. Still, there are times when these items wear more quickly than they should, and sometimes this state of affairs will prompt a manufacturer to look into reasons why. Sometimes they find conditions that cause excessively fast wear in trucks that are worked hard, though not overworked. And this may lead them to publish technical-service bulletins that take heavyduty service into account. Often, as we ve seen more than once in Brake Figure 5 25 Tech/Talk, a procedure that one vehicle manufacturer publishes to deal with a condition in their own vehicles can turn out to be applicable to other manufacturers products. For example, GM was the first manufacturer we recall to recommend that smooth, evenly worn, runout-free rotors be used as is if available in a matched pair. Now, most other manufacturers have joined them in recommending that course of action. But not all TSBs are universally applicable, as you ll note when reading what follows. The bulletins we re about to quote, addressing accelerated front brake-pad wear, do appear to be model-specific. They involve modifying the affected trucks original factory configurations and should be confined to the models described, under the conditions noted. Chevrolet, GMC Suburban General Motors has issued several TSBs regarding popular trucks that are often heavily loaded and may, as a result, wear brake pads rapidly. The ones we re considering cover two- and four-wheel drive, Chevrolet and GMC Suburbans, regular and crew cab C/K pickups and cab/chassis as well as G- series vans. TSB numbers

28 include A (which supersedes similar, but without the A suffix) and A (also an update of a previous notice.) Certain of the recommendations in these bulletins apply only if specific optional equipment is present; factory-installed option codes for these trucks are listed on a card typically glued to the inside of the glove box. The first part of this wear complaint is easy to deal with to discard, in fact, as the problem was the composition of the trucks OE rear brake shoes. By now, it s a safe bet they ve all been discarded. But that s not the end of the story with Suburbans. GM says new rear shoes alone won t solve the problem in these big SUVs; a new proportioning valve also needs to be installed. The proportioning valve kit part number, for Suburbans, is Valve kit # is for Suburbans. These trucks may also be subject to leads/pulls on brake application. If there is such a complaint, the bulletins recommend checking the relative wear of inboard and outboard front pads. If an inboard pad is worn noticeably more than its partner, clearance between the caliper and steering knuckle bracket stop (Figure 5) may not be adequate Dodge Ram 2500 Pickup Meanwhile, Chrysler issued a TSB similar to GM s regarding accelerated front brake-pad wear in (what were then called Dodge) Ram 2500 and 3500 series Figure 6 pickup models from What does accelerated front-pad wear mean? According to Chrysler TSB # , it means the front brake pads needed to be replaced at least four times before the rear brake shoes need to be replaced once. That s probably not a bad rule of thumb. If front pad wear is accelerated, Chrysler recommends switching to revised front pads in both 2500 and 3500 series trucks. (The following list shows part numbers for revised-spec MoPar OER pads from the TSB. Suitable aftermarket friction materials are probably also available.) Series GVW Pad Part No ,500 lbs AA ,800 lbs. (4X2) AA ,800 lbs. (4X4) AA 3500 (all) AA Chrysler also recommends switching the rear brake shoes and installing a new hold-down spring package in all 3500 series Ram pickups that wear out their front disc-brake pads too quickly. The OER shoes listed carry MoPar P/N AA and presumably are stickier to carry a bit more of the stopping load than the original shoes did. Here s a significant change that only a few trucks may need: Chrysler calls for a hydraulic system modification to 8,800-GVW, 2500-series trucks only and not even to all of them. We re including it here for informational purposes (its unusualness makes it thoughtprovoking), as odds are that any trucks flogged this hard since 1997 are already dead and recycled: If and only if one of these trucks is steadily operated at at least 75% of GVW (6,600 lbs.), then the TSB says rear wheel cylinders (Figure 6) should be increased in size to 27mm ID (MoPar PN ). But Chrysler does not recommend nor endorse a change in wheel-cylinder bore size under any other set of conditions. 26

29 As seen in Brake Tech/Talk Make sure that circuit has a good ground connection! Whenever a diagnostic trouble code (DTC) points to a problem in a particular circuit, you should check the integrity of the actual circuitry (wiring, connectors, etc.) before replacing any electronic or electromechanical components in that circuit. This practice always makes sense, and a condition that may arise in certain Honda Accord V-6 models bears this out. In fact, the manufacturer suggests you check a specific ground connection if you encounter a certain set of DTCs. Ground connection G204 (Figure 4) may be the only thing wrong if you come across ABS DTCs 31 and 33 in the Accord V-6s under discussion. (DTC 31 indicates problems with the right-front inlet solenoid circuit; DTC 33 is for the same circuit on the other side.) A poor G204 ground could set another pair of ABS DTCs in models. They are DTC 34 (reference voltage, or VREF signal) and DTC 61 (automatictransmission shift position, or ATSFTP signal.) G204 connects a black wire (lead C7) to ground, making the third connection to ground from the ABS/TCS control unit. The other two black wires (leads A1 and C12, grounds 1 and 2 respectively) connect to ground together at ground connection G206. Figure 4 So before replacing parts or diving too deeply into the troubleshooting process, make sure these ground connections are clean, tight and intact electrically. And start with G204 if you see the DTCs just discussed. Pump motors need good grounds, too While Honda service manuals call for replacing the ABS modulator unit if you find DTC 51 or 53 (indicating motor locked and motor stuck on, respectively) on several models from the turn-ofthe-century period, the manufacturer adds there s one more thing to check before buying this pricey part on behalf of your cus- tomer: Make sure the ground for the pump is clean, tight and electrically intact. Either of these DTCs may be set by a poor ground. Honda makes a point of stating that if you clear the codes but then the light re-illuminates and the DTCs reset during a test drive, the cause may be a poor ground connection. Either way, when you take into consideration how much the pump costs, you re providing a genuine customer service by not replacing it until you ve made sure the condition isn t just the result of an easily checked, easily fixed, bad ground connection. Model Years Accord Civic Civic Hybrid CR-V Element Insight Odyssey Pilot S

30 As seen in Brake Tech/Talk Technicians dictionary It helps when we agree on what terms mean! Every now and then rotors that are too thin to use get reused and ones that may still be good get chucked out because of confusion over a couple of terms that are often thrown around as if everyone knows exactly what they mean. So now s our chance to eliminate confusion by putting their definitions in black and white. DISCARD: When your measurement (Figure 4) shows that a rotor has reached the thickness the car manufacturer lists as the discard spec, throw it away! Even if the rotor was thicker than this number when you first checked it, and it only reached this dimension (or worse, less!) by resurfacing, it s not safe to use. We re not just talking about the fact that, as a rotor gets thinner, it s less able to absorb/dissipate and otherwise cope with the heat that s normally generated in braking. Additional possible consequences include brake fade and rotor warping, which are bad enough. Worse, a too-thin rotor combined with worn pads (and the new pads you re installing are going to wear; they re expected to) may allow a piston to pop out of the caliper, leading to catastrophic failure. This may not happen right away or even often but it can, and it s a condition we can all live without. MACHINE TO: If you find a rotor worn to this thickness and it needs resurfacing, it really needs replacing because cutting it will take it below this spec. On the other hand, if it s uniformly worn to this dimension, and no less, it may be fine for reuse as is, if its surfaces are smooth. (Make sure its mate on the axle is also good to reuse as is, or braking could be uneven, side to side.) Then again, if a rotor measures above this spec but needs resurfacing, it ll be OK to use if, once resurfaced, it meets or exceeds the machine to dimension. Cut it below this number and you re in discard territory. Time to recycle the old rotor! Figure 4 28

31 Technicallyspeaking Your Favorite Shop Tools By Ron Henningsen Undercar Digest Technical Editor Everybody has their favorite tools, but as most of us know, some are more necessary than others. We refer to these as foundation tools. In the day-to-day business of repairing automobiles we sometimes look at tomorrow s appointments to see what s coming in and think about what tools will be necessary to get the job done efficiently. Sometimes a vehicle shows up requiring the immediate use of a specific tool. 1 As an example, a vehicle in for repairs had illuminated checkengine and ABS lights. 2 For example, this Mahle TechPRO 3 functions as a scan tool calling up diagnostic codes, repair procedures, further tests, operations and various fault modes. Using a tool such as this is extremely convenient, up to date and in many instances expedites the actual diagnosis and repair. 5 Torque wrenches have come along way from the old beam units. This digital torque wrench, although still the click-type, gives the technician what he needs. It s important to calibrate this tool on a prescribed schedule for it to do its job. Here s a close-up of a modern torque wrench. You can easily comply 7 with the torque-angle reading after dialing in a specific torque setting. When the wrench clicks you simply back off the pressure and the screen shifts to a degree reading, and then continue turning the torque wrench until the degree of movement is reached. Accurate, complying with specifications and doing the job right is what using a modern torque wrench is all about. The vehicle was owned by an infrequent customer who had been there two or three oil changes ago, and there was a notation about the ABS light, and a comment that the customer declined to have it checked out. To perform the analysis on this 2004 Toyota truck it s mandatory to be able to perform a diagnostics check. A scan tool that will work on our tablet or laptop can come in handily. 4 6 Every shop should also have access to diagnostic reference information as shown on this shop computer. Technicians are instructed to check for service bulletins, recalls and other items on any vehicle they work on, especially on a complex job. Modern torque wrenches, either 3 8- or ½-inch drive, frequently have digital readouts as those shown. 29

32 8 In the area of finding a better mousetrap, here s the recently Ingersol- Rand power-socket line. These sockets are designed to loosen hardto-loosen or frozen fasteners, such as some of the crank bolts on various engines. This socket fits a standard impact wrench. 9 Here s a close-up of the socket. It works very well. If you are interested in the physics of the socket, you can find areas of discussion on a variety of blog sites Brake-line tubing straighteners are a dynamic tool. It s great to use since brake lines coming in bulk come in a coil. You can cut it and flare it yourself and improve your profitability. This is my personal tool but I have had it on loan to a shop for six years. When I have need of it, the shop delivers it back to me, and picks it up when I am done. It s one of the most popular among technicians. 12 A ball-joint press is an old friend at most shops. The presses have remained constant except for a few new adaptors for modern ball joints or bushing, but it is a very profitable tool. 13 Here s an old Chevy S10 Blazer the owner is in love with. It has dual batteries, a powerful stereo system, a rebuilt transmission and a reworked powerful engine. He asked that new urethane bushings put in every suspension part on the vehicle. As you might expect, we replaced all the ball joints as well, using the ball-joint press. 14 In addition to the rear stabilizer bushings, the front springmount bushings were replaced with new urethane product. The old ones were pressed out and the new ones pressed in. The repair ticket on this truck for all the bushings, including the ball joints, was in excess of $2,000, all at the request of the customer. Here s another must for modern-car work a TPMS tool. This one is from Bartec. A test procedure, I believe, should be done on every TPMS-equipped vehicle that comes into a shop. Test and full service is becoming commonplace. 30

33 More solid tech for less money than you ll find anywhere. Subscribe: Toll Free or Volume 24, No. 10 Volume 24, No. 10 February 2014 Service Alert: Ford Fusion steering problems Problem recognized: 2013 Ford Fusions built April may have steering-gear jams or impairedsteering problems. Additional information: Ford is recalling Fusions to replace faulty steering gears that may have a loose clip, which can lodge internally inside the steering gear. Recall no.13v : The recall, issued April 31, This month we take a look at the new Chevrolet Cruze model with the non-watts rear suspension. Later weʼll talk about some light-duty repairs in connection with newer vehicles. The Chevrolet Cruze has maintained the same basic design determined by GM to be a flexible and reliable concept on the earlier models. The car weʼre Chevrolet Cruze Non-Watts-linkage rear suspension What s Inside Chevrolet Cruze: tools & techniques for undercar service Torque-angle setting on late-model vehicles What independent shops need to know to work on new vehicles Chevrolet Cruze Eco front-suspension overview Copyright 2014 M D Publications Inc. Reproduction Strictly Forbidden 1 calls for steering-gear removal. Dealers are replacing faulty units and checking alignment and sensors for steering at no charge to the customer. Have your customers with these cars check for a reference letter from Ford posted in late April for details. Contact a franchised dealer or have the vehicle owner call the Ford Relationship Center at Alignment & Chassis Tech/Talk (ISSN ) is published monthly by M D Publications Inc., 2034 W. Vista, Springfield, MO One-year subscription USA and US possessions is $69, all other countries is $80, payable in US dollars only. Address correspondence to Alignment & Chassis Tech/Talk, P.O. Box 2210, Springfield, MO , telephone (417) , or editor@mdpublications.com. Information contained in Alignment & Chassis Tech/Talk has been carefully compiled from industry sources known for their reliability, but M D Publications does not guarantee its accuracy. Periodicals postage paid at Springfield, MO. POSTMASTER: Please send address changes to Alignment & Chassis Tech/Talk, P.O. Box 2210, Springfield, MO PRINTED IN THE U.S.A. looking at has the standard rear axle without the Watts (sometimes called Z-bar) linkage, which allows the axle to travel vertically while preventing sideways motion. The rear axle is supported at the upper unibody by the upper isolator bushings and shockabsorber mounts. Coil springs are sandwiched Service Alert Hino recalling trucks for parking-brake problem defective aftermarket Toyota taillights being recall Hino a subsidiary of To recalling certain trucks built years because of a p with the parking-brake control Problem identified: Hino h found that unusually fast wear c occur between moving parts in t parking-brake control handle if e or both of two conditions occur: 1 The driver repeatedly releases the parking brake by hitting the release button on the back of the handle wi out holding the handle as it moves through its release arc; 2) The parking-brake cable is improperly adjusted. Look at the illustration (Figure 1) Hino included in its Safety Defect and Noncompliance Report to NHTSA: The manufacturer says that letting the parking-brake lever fly by palm-smacking the release button without holding the handle can increase the friction between the pin, which engages the cable in the lever, and the long hole in which the pin slides; this leads to rapid wear between the parts. In addition, repeated operation of a parkingbrake cable that is stretched due to the repeated operation of the parking brake could increase the contact force between the cable joining [the] pin and the long hole in the slide area of the parking brake Figure 1 What s Inside Nissan/Infiniti: burnishing technique for new brakes...2 Electronic parking brakes: retracting caliper pistons...3 Tips for servicing ABS electronics...4 Thumbnail Tech/Specs: 2014 Nissan Versa Note SL hatchback...7 Brake Tech/Talk (ISSN ) is published monthly by M D Publications Inc., 2034 W. Vista, Springfield, MO One-year subscription USA and US possessions is $69, all other countries is $80, payable in US dollars only. Address correspondence to Brake Tech/Talk, P.O. Box 2210, Springfield, MO , telephone (417) , or editor@undercardigest.com. Information contained in Brake Tech/Talk has been carefully compiled from industry sources known for their reliability, but M D Publications does not guarantee its accuracy. Periodicals postage paid at Springfield, MO. POSTMASTER: Please send address changes to Brake Tech/Talk, P.O. Box 2210, Springfield, MO Copyright 2014 M D Publications Inc. Reproduction Strictly Forbidden 1 continues next page PRINTED IN THE U.S.A. Alignment Tech/Talk Eight pages every month of cuttingedge information that keeps your technicians well informed and the alignment rack profitable. Authored by an ASE Master Technician, Alignment Tech/Talk concentrates on full-color procedural coverage with explanations covering questions of what, when and why. Special Alert Bulletins are published each month as well. If your shop has an alignment rack, it should have Alignment Tech/Talk. Available in print or digital format. 12 monthly issues $69 U.S. funds Brake Tech/Talk Eight pages every month of concise and easy to understand information covering both traditional and ABS braking systems. Color diagrams and photographs accompany the procedural instructions provided by a brake industry veteran technician. A well-informed brake technician can make a true bottom line difference in any retail shop. Special Service Bulletins are included in each issue. Available in print or digital format.