Spring Brake Application

Size: px

Start display at page:

Download "Spring Brake Application"

James Tyler Chapman
5 years ago
Views:

Technical Tip Maxibrake I Series Spring Brakes Disassembly, Inspections and Reconditioning Instructions Maxibrake I Series spring brake products are mechanical devices and are subject to wear after

Haldex recommends inspection intervals as follows: Minor Brake Inspection 1 Year or 40,000 miles [whichever occurs first] Perform pneumatic leak test - service brake Perform pneumatic leak test -

1 Technical Tip Maxibrake I Series Spring Brakes Disassembly, Inspections and Reconditioning Instructions Maxibrake I Series spring brake products are mechanical devices and are subject to wear after extended use. Periodic inspection and service is required to assure satisfactory service. Haldex recommends inspection intervals as follows: Minor Brake Inspection 1 Year or 40,000 miles [whichever occurs first] Perform pneumatic leak test - service brake Perform pneumatic leak test - park brake Inspect pushrod boot for cuts/cracks Inspect chamber vent holes [clear contamination as necessary] Major Brake Inspection 3 Years or 120,000 miles [whichever occurs first] Install piston repair kit # RN21AL Replace service brake diaphragm (included with kit) Replace pushrod boot assembly (included with kit) Maxibrake I Series Spring Brake Operation The operating principle is sound and simple. The service chamber applies the foundation brake with the application of air pressure. The power spring, normally held-off with air pressure, applies the brake mechanically when the air pressure is removed. Normal Driving Spring Brake Application Service Brake Application WARNING - Spring brake chambers contain a spring with high force. Disassembly and maintenance should only be performed in full accordance with manufacturer s written instructions. CAUTION - Always block wheels to prevent vehicle from moving when deactivating the air brake system.

the Maxitool (4031108) shown in Fig.1 and a bracket (4031004).

Mounting the unit on the bracket and securing with mounting nuts will facilitate

Mark location of service inlet port on clamp band with respect to the spring chamber so

Loosen clamp band nuts and bolts and remove clamp bands. Fig. 4 5.

Break the jam nut loose from the flange nut. Fig. 6. Fig. 7 Fig.8 Fig. 9 Fig. 10 7.

Remove jam nut and flange nut from pushrod. Fig. 7 8.

Free the pushrod bushing from the piston by inserting the Maxitool shaft or pushrod

2 Technical Tip 1. Disassembly and re-assembly can be easily and safely accomplished using a shop press or the Maxitool ( ) shown in Fig.1 and a bracket ( ). Drawings are available upon request. Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig Mounting the unit on the bracket and securing with mounting nuts will facilitate disassembly with the Maxitool. Fig Mark location of service inlet port on clamp band with respect to the spring chamber so that the unit can be re-assembled to the original configuration. Fig Loosen clamp band nuts and bolts and remove clamp bands. Fig Remove the pressure housing and diaphragm. Fig Break the jam nut loose from the flange nut. Fig. 6. Fig. 7 Fig.8 Fig. 9 Fig Press in on the pushrod plate to relieve return spring force. Remove jam nut and flange nut from pushrod. Fig Pull out pushrod, return spring and spring retainer. Fig Free the pushrod bushing from the piston by inserting the Maxitool shaft or pushrod through the piston tube and tapping lightly. Remove and discard the plastic bushing. Fig Place the unit on a bench with the mounting studs facing up. Apply 100 psi to the emergency port and spray soapy water inside the piston tube. Inspect for bubbles at bottom of tube where the stainless steel tube meets the aluminum piston casting. If the joint between the piston tube and casting is leaking, replacement of the unit is recommended. Fig. 10

Use safe shop practices to assure fixturing holds the actuator securely. Fig. 11 Fig. 11 Fig. 12 Fig.

If a shop press isn t available, insert the Maxitool from the service side of the unit through

Assemble machined locator bushing on Maxitool with the small diameter toward piston tube.

Tighten nut until the Maxitool is centered and resting firmly against the spring support then

(Spring does not need to be fully compressed) If using a shop press, bring ram down against

Fig. 14 15. Remove the eight (8) cap screws holding the spring support. Fig. 15 Fig. 15 Fig. 16 Fig.

3 Technical Tip 11. Place unit in shop press capable of 4,000 pounds force and 8 inches of travel. Use safe shop practices to assure fixturing holds the actuator securely. Fig. 11 Fig. 11 Fig. 12 Fig. 13 Fig If a shop press isn t available, insert the Maxitool from the service side of the unit through the piston tube until the round plate and locater contacts the spring support. Fig Assemble machined locator bushing on Maxitool with the small diameter toward piston tube. Screw nut on the Maxitool shaft and tighten against the machined locator. Fig Tighten nut until the Maxitool is centered and resting firmly against the spring support then tighten the nut three full turns fully releasing the spring pressure. (Spring does not need to be fully compressed) If using a shop press, bring ram down against the spring support and apply only enough pre-load to relieve spring pressure on the cap screws. Fig Remove the eight (8) cap screws holding the spring support. Fig. 15 Fig. 15 Fig. 16 Fig. 17 Fig Raise the press or gradually back off the nut on the Maxitool until all pressure is off of the spring. Fig Remove the Maxitool, power spring and spring support. Fig Remove the piston assembly from the cylinder being careful not to damage the end of the tube. Fig. 18

Technical Tip Disassembly Continued 19. Remove and discard the felt wiper and O-Ring from the piston. Take care to avoid damaging the piston groove surfaces with any tool used to remove the O-ring.

Use a sharp pointed instrument to remove the bushing; work clockwise from the cut to pry the bushing out of the groove. Fig. 20 21. Wash all of the metal parts in cleaning solvent. Fig. 21 Fig.

Scuffs or light scratches in the coating can be smoothed with a fine emery cloth or steel wool.

4 Technical Tip Disassembly Continued 19. Remove and discard the felt wiper and O-Ring from the piston. Take care to avoid damaging the piston groove surfaces with any tool used to remove the O-ring. Fig. 19 Fig. 19 Fig Remove the O-Ring and nylon bushing from the cylinder center boss. Use a sharp pointed instrument to remove the bushing; work clockwise from the cut to pry the bushing out of the groove. Fig Wash all of the metal parts in cleaning solvent. Fig. 21 Fig. 21 Inspection & Reconditioning Cylinder Assembly Check the bore for rust, scoring, loose coating or dents. Missing paint is not a problem as long as the cylinder bore is not rusty. Scuffs or light scratches in the coating can be smoothed with a fine emery cloth or steel wool. Also check for and remove any burrs around the cap screw holes that might cut the O-Ring during re-assembly. Make sure the mounting studs are not bent and the threads are not damaged. Assure surface is smooth with no defects that will lead to accelerated wear. Piston Assembly Check for and remove all nicks, burrs and scratches from the piston skirt and grooves. The piston tube is stainless steel and should be free of scratches. Proper care of the piston tube is important to assure reliable performance. The rubber dust boot is very effective to keep the piston tube clean during use. Piston assemblies can be replaced if damaged. See Service Part List. Power Spring Replace the power spring if evidence of corrosion or peeling paint is found. See Service Part List.

Technical Tip Re-assembly Fig. 1 Fig. 2 Fig. 3 Fig. 4 1.

NOTE: Bushing must be installed so the side with the beveled edge on the inside diameter faces toward the

Install the oil soaked felt wiper in the groove next to the open end of the piston. Fig. 3 3.

Grease the inside of the cylinder with a thin even coat of the lubricant provided (M4041489). Fig. 4 5.

Push the piston assembly all the way in, taking care to not cut or damage the small O-Ring with the end of

Also take care that the large O-Ring is not damaged as it passes by the cap screw holes in the cylinder.

If using Maxitool, insert through piston assembly.

5 Technical Tip Re-assembly Fig. 1 Fig. 2 Fig. 3 Fig Install nylon bushing in the outer most groove of the boss on end of cylinder. NOTE: Bushing must be installed so the side with the beveled edge on the inside diameter faces toward the inside of the cylinder. Lubricate and install small O-Ring in the inner groove. Fig 1 & Fig. 2 2.Install the oil soaked felt wiper in the groove next to the open end of the piston. Fig Lubricate and install large O-Ring in the pre-lubricated center groove of the piston assembly. Fig Grease the inside of the cylinder with a thin even coat of the lubricant provided (M ). Fig Insert piston assembly in cylinder, holding felt wiper in place as piston is inserted. Fig Push the piston assembly all the way in, taking care to not cut or damage the small O-Ring with the end of piston tube when inserted. Also take care that the large O-Ring is not damaged as it passes by the cap screw holes in the cylinder. Fig Assemble spring support and power spring using a shop press or the Maxitool. If using Maxitool, insert through piston assembly. Run the Maxitool guide bushing and nut on the shaft and tighten slowly. Take care to center the spring with the piston hub and spring support. Fig. 7 Fig. 5 Fig. 6 Fig. 7 Fig Tighten nut down (or run down in shop press) until holes in the spring support align with the holes in the cylinder. Install the eight (8) cap screws securing the spring support to the cylinder. Fig. 8

Technical Tip 9. Alternately tighten the screws to 125 in-lbs of torque. Fig. 9 Fig.

Install the pushrod bushing into the piston.

Assemble spring retainer (cupped side against pushrod plate) and pushrod return spring on

Secure loosely with the flange nut. Fig. 11 12.

step 3, and apply pressure to the housing to squeeze the diaphragm.

Tighten the nuts to between 120 and 180 inlbs of torque.

6 Technical Tip 9. Alternately tighten the screws to 125 in-lbs of torque. Fig. 9 Fig. 9 Fig. 10 Fig. 11 Fig Remove the Maxitool or remove the unit from the shop press. Install the pushrod bushing into the piston. Tap lightly and make sure the bushing is inserted properly. Fig Assemble spring retainer (cupped side against pushrod plate) and pushrod return spring on the pushrod; install the rod through bushing and piston tube. Secure loosely with the flange nut. Fig Install diaphragm with the crowned surface in the pressure housing and center over the cylinder. Align the port boss on the pressure housing according to the marks put on in disassembly step 3, and apply pressure to the housing to squeeze the diaphragm. Align clampband assembly with the pressure housing and cylinder flanges. Fig Tighten the nuts to between 120 and 180 inlbs of torque. Make sure the bolts are evenly tightened on both sides. Fig. 13 Fig. 13 Fig. 14 Fig. 17 Fig Apply shop air pressure between 95 and 105 psig to the spring chamber so that the spring is fully compressed and the piston tube is approximately flush with the cylinder boss. Fig Adjust the flange nut on the pushrod until there is a 1/16 to 1/8 clearance gap between the piston tube and the flange nut. FIg If a scale is not available, a U.S. quarter may be used to gage the distance between the flange nut and piston tube. Fig. 16

Technical Tip Re-assembly Continued 17. Secure in position with the jam nut. Test both chambers for air leaks. Fig.17 Fig. 19 18. Install all 4 vent plugs in cylinder.

7 Technical Tip Re-assembly Continued 17. Secure in position with the jam nut. Test both chambers for air leaks. Fig.17 Fig Install all 4 vent plugs in cylinder. Note: Bottom most plug must be removed upon installation. 19. Install reinforcement tube according to Maxibrake I Spring Brake Reinforcement Tube Install Instructions (L55288W) on the Web. 20. Install boot on the pushrod. Service Kit Part Number RN21AL contains all of the service items to recondition two (2) Maxibrake units; two (2) complete sets of O-Rings, oil soaked felt wipers, pushrod bushings, piston tube bushings and a special lubricant formulated exclusively for the Maxibrake spring brake. Contents of Service Kit (RN21AL) Description Quantity Part Number O-Ring SMall 2 M O-Ring Larger 2 M Felt Wiper 2 M Nylon Bushing 2 M Pushrod Bushing 2 M Lubricant (3 oz. tube) 1 M Vent Plug 8 M Diaphram (type 30) 2 DP30 Boot Assembly 2 M

8 Technical Tip Item Description Type 20 Type 24 Type 30 Type 36 1 Pressure Housing Assembly (1) M M M M Clampband Assembly M M M M Diaphragm DP20 DP24L DP30* DP36 4 Pushrod Assembly -J = 8.00 M102560BB M102580DB M102732AC M14096DB 5 Return Spring Retainer M Return Spring M M Pushrod Bushing (2) M Spring Support M M Power Spring - #50 M Power Spring - #60 M Power Spring - #75 M Felt Wiper (2) M O-Ring - Large (2) M Piston Assembly M M M Vent Plug M Cap Screw M M Cylinder Assembly (1) M M M M O-Ring - Small (2) M Nylon Bushing M Flange Nut (5/8-18UNF) M Jam Nut (5/8-18UNF) HW5 20 Dust Boot Kit M * (1) Pressure Housing Assemblies come with a single 3/8 NPTF side inlet port. Cylinder Assemblies come with a single 3/8 NPTF inlet port oriented 90 from the mounting studs. (2)These items are included in the Service Kits, RN21AD (for repair of a single Maxibrake unit) RN21AE (for repair of two Maxibrake units) RN21AL (for repair of two transit bus units) *Included with kit RN21AL

INSPECTION & MAINTENANCE BULLETIN ARI 1301/1302 1" Plug Type Angle Valves

INSPECTION & MAINTENANCE BULLETIN ARI 1301/1302 1" Plug Type Angle Valves Item # Description Item # Description 1 Body 12 Washer 2 Packing Retainer 13 Bushing 3 Packet Set 14 Bolt 4 Jam Nut 15 Yoke 5 Stud