BD Remote Mount Exhaust Brake

Transcription

1 7 January 2014 # / GMC/Chevy Duramax (I-00072) 1 4-Bolt Flange 3.5 Casting (OEM Exhaust) Marmon Casting (4.0 Aftermarket Exhaust) GMC/Chevy LB7 Duramax BD Remote Mount Exhaust Brake Part Number Application Duramax with 3.5 Stock Exhaust, Single Alternator Duramax with 4.0 Aftermarket Exhaust, Single Alternator Serial # Date Purchased Purchased from Installed by *** Please read this manual before starting installation. *** OWNER S MANUAL - LEAVE IN GLOVE BOX Install Manual Part # I Printed in Canada

2 7 January 2014 # / GMC/Chevy Duramax (I-00072) 2 T A B L E O F C O N T E N T S Welcome... 3 Brake Kit Contents... 3 Pre-Installation... 4 Special Tools Required... 4 Notes On Connectors... 4 Brake Valve Installation (3.5 Exhaust Only)... 5 Brake Valve Installation (4.0 Aftermarket Exhaust Only)... 7 Solenoid Valve Installation... 9 Air Supply Air Regulator & Air Compressor Install Power Hook-up Main Wiring Harness Installation Main Switch Installation V Power Wiring & Plumbing Diagram s In Cab DFIV Wiring Wiring and Plumbing Diagram DFIV Calibration Maintenance OPERATING GUIDELINES Exhaust Back Pressure Testing Air Actuated Brakes Air Brake Troubleshooting Guide... 21

3 7 January 2014 # / GMC/Chevy Duramax (I-00072) 3 Welcome Thank you for purchasing a BD Exhaust Brake. This manual is divided into different areas to assist you with your installation and operation of your braking unit. We strongly suggest that you write down the kit and serial numbers of your unit in the spaces provided and retain this manual for any future reference. Brake Kit Contents DURAMAX LB7 EXHAUST BRAKE KIT 3.5 Stock Exhaust Part # Qty. Description C 1 Pump control Kit B 1 Compressor / Regulator Kit B 1 Regulator & Pump Harness Exhaust pipe adapter Marmon exhaust clamp Exhaust seal clamp Bolt Exhaust Brake Valve Assy Air Brake snorkel (One for Air Solenoid / One for Brake) DFIV Control Kit Exhaust gasket DURAMAX LB7 EXHAUST BRAKE KIT 4.0 Aftermarket Exhaust Part # Qty. Description C 1 Pump control Kit B 1 Compressor / Regulator Kit B 1 Regulator & Pump Harness Exhaust pipe adapter Marmon exhaust clamp Exhaust seal clamp Marmon-Style Exhaust Brake Valve Assy Air Brake snorkel (One for Air Solenoid / One for Brake) DFIV Control Kit

4 7 January 2014 # / GMC/Chevy Duramax (I-00072) 4 Pre-Installation Before installation can begin, we must take a look at any other requirements or options for your particular application. If the driver likes gauges, another handy option is the Brake Pressure Gauge Kit. This gauge will allow you to monitor the pressures being developed by the exhaust brake. Special Tools Required Measuring tape or ruler Drill with 1/8 bit and Unibit Sawsall or hacksaw Crimping Pliers Test light Notes On Connectors The kit includes a number of Posi-Tap connectors (Gray or Red/Black/Green or Yellow) to tap onto OEM wiring. It is important to select the correct color of connector so that it matches the gauge of the OEM wire that it is being installed on. Using the incorrect connector could cause an inadequate connection and/or the OEM wire could be severed. OEM Wire 18-22ga 12-18ga 10-12ga Posi-Tap Color Red Black Yellow Though these connectors offer a quicker installation, the best option would be to solder the wires and isolate the joints with heat shrink or liquid electrical tape. Proper soldering techniques should be used to ensure adequate connections. Posi-Tap Connector Usage Diagram Insert Hot Wire Tighten Strip Leads Insert & Tighten Make sure to center the wire when tightening the pierced portion of the hot wire to make a solid connection. The ground terminals of the vehicle s batteries should be disconnected before performing any piercing/posi-tapping onto any ECM/PCM wire.

5 7 January 2014 # / GMC/Chevy Duramax (I-00072) 5 Brake Valve Installation (3.5 Exhaust Only) From underneath the vehicle, remove the 4 nuts at the flange that hold the intermediate pipe to the down pipe. Remove two of the exhaust pipe hanger pins from the exhaust hangers to allow the rear section of the exhaust to hang down and provide access to the exhaust. It may help to spray WD40 on the pins to slide the rubber hangers off. SUPPORT THE REAR SECTION OF THE EXHAUST OR IT COULD FALL RESULTING IN INJURY OR DAMAGE. Measure and mark the intermediate exhaust pipe 5 1/2 from the flange and cut it off. Do not cut the down pipe. Clean off the cut end of the intermediate pipe with a file (to remove burrs left from cutting the pipe) and insert the adapter pipe and pipe clamp loosely. (You may have to tap the adapter on with a soft-faced hammer or a piece of wood) Clean off any old gasket material from the down pipe flange and install the BD Brake valve assembly with the new gasket provided. Install the 4 mounting bolts. Ensure that the brake is properly aligned and tighten the 4 mount bolts. Band Clamp THE VALVE ACTUATING CYLINDER MUST BE POSITIONED TO THE MIDDLE / INSIDE OF THE VEHICLE. REMOVE THE BLACK SHIPPING CAP FROM RELEASE VALVE VENT OR THE BRAKE MAY STAY ENGAGED.

6 7 January 2014 # / GMC/Chevy Duramax (I-00072) 6 Slide the rear adapter pipe forward and secure it to the brake with the supplied v-band clamp. Re-install the rubber exhaust hangers that were removed in step #2 checking for proper exhaust alignment, and then tighten the band style clamp. NOTE: WHISTLING FROM THE EXHAUST BRAKE WHILE IT IS ENGAGED INDICATES AN EXHAUST LEAK BETWEEN THE BRAKE AND THE ENGINE.

7 7 January 2014 # / GMC/Chevy Duramax (I-00072) 7 Brake Valve Installation (4.0 Aftermarket Exhaust Only) From underneath the vehicle, locate a straight section of pipe at least 10 long try and keep it as close to the engine as possible. U-Joint Driveshaft Overaxle pipe to muffler Remove the 7 1/4 section of pipe with a sawsall or cutoff saw. Clean up the cut ends of the pipe with a file to remove any burrs. Slide the supplied pipe adapter flanges over each side of the cut exhaust. The flange closest to the front of the vehicle will need to be welded. A good, clean weld is needed to seal the high backpressure that the exhaust brake will create. Rear of Truck Weld Here Use V Clamp Use SS Band Clamp Once you have finalized the fit by welding the front flange, tighten the two supplied V-band clamps around both flanges on either side of the exhaust brake. Secure the rear flange with the supplied stainless band clamp. The exhaust brake should now be held securely in place.

8 7 January 2014 # / GMC/Chevy Duramax (I-00072) 8 Valve installed on a 2005 LLY Duramax IMPORTANT NOTES ON VALVE INSTALLATION THE VALVE ACTUATING CYLINDER MUST BE POSITIONED TO THE MIDDLE / INSIDE OF THE VEHICLE. REMOVE THE BLACK SHIPPING CAP FROM THE RELEASE VALVE VENT OR THE BRAKE MAY STAY ENGAGED. WHISTLING FROM THE EXHAUST BRAKE WHILE IT S ON INDICATES AN EXHAUST LEAK BETWEEN THE BRAKE AND ENGINE.

9 7 January 2014 # / GMC/Chevy Duramax (I-00072) 9 Solenoid Valve Installation The solenoid valve assembly controls the application of air pressure to the exhaust brake valve. There is no viable place to mount this assembly on the passenger side of the vehicle because of the exhaust system, so it must be mounted on the driver side. The solenoid valve should be mounted as close as possible to the exhaust brake so that it actuates quickly. There is a wiring harness running along the outside of the driver s side frame rail and is secured with plastic clamps. Locate one of the clamps closest to the rear transmission crossmember and pop the clamp mount out of the frame. This should leave a hole which is approximately 3/8 in diameter. Using the hardware provided, mount the Solenoid Valve Assembly to the inside of the frame rail. The brown ground wire with the ring terminal is also attached here. NOTE: It may be necessary to remove the fitting in the top of the air solenoid to install the mounting bolt.

10 7 January 2014 # / GMC/Chevy Duramax (I-00072) 10 Air Supply Insert one end of the 1/4 plastic hose into the quick-connect coupler on the quick release valve on the brake air cylinder and route it over the drive shaft/transfer case to the 90 fitting on the #1 port of the solenoid valve. Cut the hose with a knife or a hose cutter, leaving some slack for routing (do NOT use side cutting pliers as the hose will be squashed and leak). Ensure the end is cleaned of any burrs and insert the loose end into the straight fitting on the solenoid valve. Two air vent snorkel assemblies are supplied in the brake kit, one for the main air cylinder and one for the air solenoid. Each snorkel assembly has 14 of ¼ plastic air hose with a grey filter on the end. Insert the free end of one snorkel assembly into the 90 fitting on the front of the brake air cylinder (the end of the cylinder where the rod comes out) and route it over the drive shaft/transfer case. Support both hoses with the 4 plastic support clamps positioned in pairs using the self-tapping screws provided. You will have to drill a 1/8 pilot hole into the cross support for the clamp screws. CARE MUST BE TAKEN NOT TO KINK THE PLASTIC HOSE OR ROUTE IT NEAR A HEAT SOURCE. Insert the open end of the other snorkel assembly into the fitting coming out of the top of the solenoid valve. Insert the end of the remaining length of ¼ plastic hose into the straight fitting on the #2 port of the solenoid valve. Route this hose, both snorkel hoses and the blue wire on the solenoid valve up into the engine bay. The hose from solenoid valve will later be attached to the regulator assembly once that is installed. The two snorkels can be run through the firewall and secured under the dash area, away from any moving parts or major heat sources. NOTE: To remove the plastic hose from the quick-connect coupler, push the outer ring toward the fitting and pull the hose out.

11 7 January 2014 # / GMC/Chevy Duramax (I-00072) 11 Air Regulator & Air Compressor Install Locate a spot just to the left of the brake master cylinder assembly and install regulator & relay assembly. You may have to remove the relay and the relay socket holder to enable access to the mounting screw. Locate a position by the air conditioner compressor to mount the pump assembly. There should be two open ended threaded bolt holes that will accommodate the two rear mounts of the air compressor nicely. Install compressor and mount assembly into the position as displayed in the photos above. Route the air supply hose that you installed on the solenoid valve over to the regulator assembly. Trim the hose to length and insert it into the straight fitting on the regulator. Cut and route a section of the 1/4 plastic air hose from the pump outlet to the 90 fitting on the air regulator. Attach the open end of the air supply hose from the air solenoid to the straight fitting on the regulator.

12 7 January 2014 # / GMC/Chevy Duramax (I-00072) 12 Power Hook-up Open the red protective cover of the remote battery connection and you will see a nut and stud attached to the positive terminal. Attach the red wire with the ring terminal & in-line fuse from the regulator & relay assembly to this terminal. Locate the bolt on the power steering reservoir bracket to the left of the protective cover and attach the black ground wire with the ring terminal to this point. Attach the blue & black wires with the female spade connectors in the regulator & relay assembly to the male connectors on the pressure switch on the air compressor. It does not matter which wire attaches to which terminal. Route the pink brake activation wire from the DFIV through the firewall and over to the regulator & relay assembly. Crimp this pink wire, the pink wire from the regulator & relay assembly, and the blue wire from the solenoid valve together, using the crimp connector with the clear plastic heatshrink. Once this is done you can shrink the heatshrink to seal the connection.

13 7 January 2014 # / GMC/Chevy Duramax (I-00072) 13 Main Wiring Harness Installation To obtain access to the accelerator pedal and wiring harness remove the dashboard bezel by pulling rearward on the corners of the bezel. Note: Placing the transmission all the way into 1 st /low gear and ensuring the tilt steering is all the way down will allow for easy removal. Remove the lower steering column panel by removing the mounting screws and unsnapping the panel from the instrument panel. You will need to find a suitable mounting location for the DFIV. Double sided tape or zap straps can be used to secure the DFIV out of harm s way. DURAMAX APPS WIRING APP SENSOR 1 SIGNAL - Pin F (Dark Blue wire Circuit 1161) At the throttle pedal, locate the accelerator position pedal sensor plug and find the dark blue wire located at pin F. Use the provided gray (or red) Posi-Tap to tap onto this wire. Connect the yellow wire on the APPS terminal of the DFIV to this point. Under the dash, by the brake pedal, locate the brake light switch and the Purple wire coming from it. With the key turned on, test the purple wire to ensure it is the correct one. This wire will have power when the key is on and power will go OFF when the brake pedal is applied. Strip away some of the insulation wrapping to expose the wire about 6-8 (a good working length) away from the brake switch. Cut the purple wire at this point and strip 1/4 insulation off each end.

14 7 January 2014 # / GMC/Chevy Duramax (I-00072) 14 Insert one end of the cut wire into the DFIV input marked COMMON and the other cut end into the FORD input. Extra wire has been provided to ease the installation. At this time you can also route the ground connection to the DFIV. You can select one of the mounting bolts or nuts that are fastened to the firewall. Be sure that it is a good solid clean ground. Main Switch Installation Measure and mark a spot for the Toggle Switch 1 5/8 up from the bottom edge of the dash panel and 1 5/8 in from the edge of the accessory panel as shown in the photo below. Drill a pilot hole with a 1/8 bit at this point. Finish drilling the hole with a Unibit to exactly 1/2. Note: This measurement must be exact as possible to ensure room for the switch on the inside of the panel. Install switch into drilled hole and secure with lock ring. Attach ground wire to a good ground then reinstall kick panel and dash bezel to finish installation. Please follow the wire diagram on page 15 to finish connecting the DFIV to the toggle switch.

15 7 January 2014 # / GMC/Chevy Duramax (I-00072) 15 12V Power Locate a switched power supply on the fuse panel, such as the one indicated in this diagram then install the brass fuse tap provided onto the HOT side of fuse which will be the side with power to it when the fuse is removed and key on. Run the power wire from the exhaust brake toggle switch over to the fuse block and connect to the fuse tap. See pages 15 and 16 for wiring diagrams. Wiring & Plumbing Diagram s In Cab DFIV Wiring Brake Activation wire leads to diagrams on next page. Connect to fuse tap or vehicle keyed power wire.

16 7 January 2014 # / GMC/Chevy Duramax (I-00072) 16 Wiring and Plumbing Diagram

17 7 January 2014 # / GMC/Chevy Duramax (I-00072) 17 DFIV Calibration Ensure the connections of the corresponding wires to the DFIV Control Module are correct as shown in the wiring diagram. To achieve the correct setting for the activation of the exhaust brake in relation to the throttle pedal the DFIV Module must be calibrated for your vehicle. Connect one end of a test light to the BRAKE terminal of the DFIV module and the other end to a good ground. With the throttle at idle, start the engine and turn on brake switch. Then, using a small flat bladed screwdriver, turn the small adjusting screw in the DFIV Module counterclockwise or clockwise until the test light JUST turns on. CAUTION: THE ADJUSTING SCREW IS A MICRO-SWITCH THAT IS VERY DELICATE, SO TURN USING SMALL ADJUSTMENTS. Test by revving up the engine to approximately 1200 RPM and releasing the throttle. As the accelerator pedal is applied the test light should turn off just before the engine starts to rev, indicating proper calibration of the DFIV Module with the APPS. Then the test light should activate again when the throttle pedal returned to idle. If not, readjust the DFIV Module so that it does. Reinstall lower dash cover. Maintenance To extend the life of the valve assembly, do not operate vehicle for an extended periods of time without activating the exhaust brake. We suggest activating the brake at least a couple times on any day you operate the vehicle to prevent any carbon or rust build-up on the inner components of the valve assembly. The hoses, wires, fittings and clamps should be inspected on a regular basis for any deterioration, damage or leaks. Following the diagrams in this manual, tracing hoses and wiring, checking continuity through electric components or checking for any lines that are disconnected, should solve any problems that may arise. If you have any problems or need replacement parts, call us at , between 8:30am and 4:30pm Pacific Time. FOR MAXIMUM EFFICIENCY USE TRANSMISSION IN TOW/HAUL MODE

18 7 January 2014 # / GMC/Chevy Duramax (I-00072) 18 OPERATING GUIDELINES Thank you for taking interest in the BD Engine Exhaust Brake. As a driver, you probably already know the need for extra braking power that your vehicle requires on the hills and long grades. With loads being towed behind you, the extra push when slowing down or maintaining speed on downward grades can prove to be a great strain on your vehicles hydraulic braking system, even to the point of burnup. These guidelines were designed to offer you a better understanding of the benefits of exhaust brakes and are partly based upon material developed by the U.S. Department of Transportation National Highway Traffic Safety Administration. The emphasis on today s vehicles is to give the consumer a product that can give them usable power with fuel efficiency. But, in the transition, the vehicles have lost their natural braking power, making it more easy for the vehicle to continue to roll and harder to stop. Of course, this gets more noticeable with the increase of weight, on or behind the vehicle. This is where an exhaust brake becomes a useful tool in increasing the driveline drag of the vehicle without the use of the hydraulic brakes. It is a tool that with maximum use, or even occasional use, can reduce wear on hydraulic braking parts and at the same time increase safety. The BD Exhaust Brake can be used to help maintain a controlled vehicle speed on a downward grade, as well as slowing the vehicle down for such times as turns or exit ramps, without you using your hydraulic brakes. But, the exhaust brake cannot be used as a parking brake or will not bring your vehicle to a complete stop. By using a BD Exhaust Brake, the life and effectiveness of your hydraulic brakes will increase. This is because of the decreased use of the hydraulic brakes in situations like hills, the wear factor is reduced and there is less opportunity for your hydraulic brakes to heat up which would reduce the efficiency. When you ride your hydraulic brakes, make hard stops or have poorly adjusted brakes, this creates high temperatures and as your brakes get hotter, the more chance there is for fade or failure. With terrain that is a series of up and down grades, the BD Exhaust Brake will aid in reducing exhaust valve warpage. Because of the power needed to pull your vehicle and load up a hill, this generates a lot of heat. When you have reached the crest of the hill and are now coasting down the other side, the heated valves are too quickly cooled. With the exhaust brake engaged, the heat loss to the valves will be reduced, which can prevent valve warpage. When the toggle switch is turned to the On position, the valve is activated every time the driver takes his foot off of the throttle pedal. When the driver puts pressure back on the throttle pedal, the throttle switch (or electronic brake module) is deactivated and the valve opens again. Exhaust brakes are designed to operate with the throttle at idle, not to be used in conjunction with cruise controls, and not

19 7 January 2014 # / GMC/Chevy Duramax (I-00072) 19 designed to aid in gear shifting. Such cases could cause damage to engine and/or the exhaust brake. The best scenario for exhaust braking is when going down hill, select a gear that lets you maintain a constant speed with little or no use of the hydraulic brakes, or the same gear that would be used to go up the same grade of hill. This also depends on the weight, load or road conditions that the vehicle will come upon. So, in summary, by using the BD Exhaust Brake, you reduce the need for use of your hydraulic brakes in situations where you need to slow down or maintain (i.e. hills, off ramps, corners, approaching speed changes or traffic lights). Reducing the use of your hydraulic brakes in these situations will reduce the heat build up, as well as wear and damage to linings and drums. And, when you reduce these factors, you save your hydraulic brakes for when you really need them (for stopping or emergencies). The BD Exhaust Brake is not a substitute for your hydraulic brakes and, cannot correct or compensate for poorly maintained or misadjusted brakes. But, when you need to slow down or maintain a constant speed, the BD Exhaust Brake will be a valuable and effective tool. Exhaust Brakes are more efficient at preventing than correcting an over speed condition. Exhaust Back Pressure Testing Air Actuated Brakes It is recommend that you purchase the BD pressure gauge kit # NOTE: The brake stop-bolt and regulator have been preset at the factory and should not need to be adjusted. You do not need to measure the air pressure in the system, just the exhaust backpressure, which is located on the cast valve.

20 7 January 2014 # / GMC/Chevy Duramax (I-00072) 20 Idle Pressure Test With the BD brake engaged and the engine at idle check the exhaust backpressure using a pressure gauge (such as BD PN ) at the test port on the brake valve. If the back pressure is below 13 psi at idle you have a number of likely causes. The most common being an exhaust leak either at the clamp joint or at the welds (only on some models). Apply the exhaust brake and have someone assist you looking for soot trails or the visible leak. Another culprit would be an exhaust manifold leak, turbocharger gasket leak, turbocharger problem or an EGR issue. If the back pressure is greater than 25psi, you will need to make an adjustment on the stop bolt. Loosen the jam nut, and lengthen the stop bolt towards the actuator, this will shorten the stroke distance. Only turn 1/4 rotation at a time and re-secure the jam nut. Retest idle pressure. We generally do not recommend adjusting the stop bolt, please consult BD before doing this as it may void your warranty. Off-Idle Pressure Test & Adjustment Your BD exhaust brake is a variable-orifice design so when the brake is active and the engine is at higher RPM the brake lever does not rest on the stop bolt. Off-idle backpressure is set by adjusting the air pressure regulator which will in turn increase or decrease off-idle exhaust backpressure. You will need to secure your pressure gauge somewhere that you can see it while you are driving. Using a long extension hose & bringing the gauge into the cab through an open window or clipping it under a windshield wiper works well. Get the truck up to speed (a downhill grade or a load in the truck is helpful) and activate the exhaust brake. Note the maximum backpressure achieved. You should get peak backpressure at higher RPM (try 3000 RPM in Drive). If you cannot reach the desired backpressure (compare table below) you can begin troubleshooting, the first step is to look for exhaust leaks either from the clamps, exhaust manifolds or feed pipes. Also look for leaks at the clamps located at the back of the turbo and also at the down pipe. If all connections are sealed, you can then use the adjusting regulator to increase the backpressure. Note that small regulator adjustments can have a significant effect on off-idle backpressure. Turning the regulator clockwise will increase pressure.

21 7 January 2014 # / GMC/Chevy Duramax (I-00072) 21 Turning the regulator counter clockwise will decrease pressure. NOTE: Over the next two weeks, the backpressure at idle may rise due to initial carbon build up on the inside of the brake housing and on the butterfly. The stop bolt may need to be adjusted again to compensate. Application GM/Chevy 6.5 GM/Chevy Duramax Ford Powerstroke Dodge Cummins V w/o 60lbs Springs Dodge Cummins V with 60lbs Springs Dodge Cummins 2002 and Newer Maximum Back Pressure 35 psi 55 psi 45 psi 40 psi 60 psi 60 psi *HD Spring part# is CAUTION: Do NOT exceed the maximum back pressure value in the exhaust system. Exceeding this pressure will force the exhaust valves open during the intake stroke which could cause engine damage. Air Brake Troubleshooting Guide Version 2 For one whenever the brake controller is powered there will be a flashing light. This shows that the unit has power and the microprocessor is functioning normally. The second LED comes on when the Brake Output is energized. For example when you press the test button. Version 2.01 and Newer This unit does away with the blinking light. There will be a Red LED that operates when the Brake Output is energized This shows that the brake is being requested to activate. The green LED will only come on once the VSS signal is met. So below 15 mph the LED will be off above 25 mph the LED will be on. As well you will notice an EBP ADJ potentiometer on the side of the brake controller. The potentiometer is only used if you run into EGR problems. Please contact BD before adjusting this.

22 7 January 2014 # / GMC/Chevy Duramax (I-00072) 22 This guide assumes that your exhaust brake system is using a DFIV and a BD air compressor. If you system uses a microswitch for throttle activation, the operation of the air solenoid and pump are the same as with the DFIV. If you are using existing on-board air, check that system as appropriate. When I let off the throttle nothing happens. Is the DFIV powering its brake output when the throttle is at idle and brake switch and ignition are both on? The brake comes on but there s little or no holdback See if torque converter is staying locked up during deceleration. If not, the engine RPM will fall to idle when the throttle is released. The brake will be ineffective without the torque converter locked up. Check off idle brake pressure. (See back pressure chart) Are you getting maximum allowable backpressure? No Check if DFIV has good power, ground and throttle signal. Check DFIV adjustment. If these things check out, but the DFIV won t power the brake output, the DFIV is likely faulty. Also check power & ground at pump relay and make sure the air solenoid has a good ground. No Check for exhaust leaks. A small leak can result in a significant decrease in back pressure. If no leaks are found try adjusting air regulator. Check for air leaks in brake system. Yes Check that when air solenoid is powered it will allow air to flow from the #2 port out the #1 port. Check that pump relay is powering pump. If pump has power but does not run, pump is likely faulty. Check for power & ground at pump relay, if these are good but relay does not click or does not power pump, relay is likely faulty. Yes Try down shifting more aggressively. More RPM will give more holdback. Transmission or torque converter could be slipping internally. Everything seems to work, but the brake valve won t close. No Yes Check that air is reaching brake air cylinder? The valve lever can be moved freely? Problem Air compressor runs in short bursts and brake is slow to apply. Air compressor runs continually. Brake is slow to release. Air solenoid or quick release valve are likely stuck, plugged or faulty. Clean or replace as required. Try dismounting the brake & cleaning the carbon out of it. If this does not work the brake valve will need to be replaced. Solution Cylinder or brake valve are seized. Remove the clevis pin on the end of the cylinder rod & see if the valve lever can be moved freely. The cylinder is stuck and will need to be replaced. There is a restriction in the air system, normally in the regulator or air solenoid. Remove the fittings from the regulator and air solenoid, you will likely find some corrosion or debris caught in them. Clean this out with a pick, small brush, compressed air and WD40 or similar lubricant. Pump relay is likely stuck on. Check operation of relay & replace as required. Debris or corrosion is restricting the quick release valve or air solenoid. Clean as required. Air solenoid could be too far from brake.