REAR CALIPER SERVICE PROCEDURE

REVISION: 03/25/94

THIS BULLETIN IS BEING REVISED FOR THE FOLLOWING REASONS:

A. SUPPLY AN ADDITIONAL TOOL NUMBER J41013 (SANDING DISC KIT) AND A VIDEO. THE TOOL AND VIDEO WILL BE SHIPPED TOGETHER TO ALL DEALERS.

1. PLEASE INSURE THAT ALL BRAKE TECHNICIANS WATCH THIS NEW VIDEO.

B. ADD ILLUSTRATIONS.

C. REVISE LABOR TIME TO INCLUDE USE OF TORQUE STICKS.

D. CHANGE THE PROCEDURE SECTION.

PREVIOUS DIVISIONAL PUBLICATION NUMBERS WERE:

BUICK 93-5-7 CANADA 93-5-111 CHEVROLET 93-138-5 OLDSMOBILE 93-T-48 PONTIAC 93-5-10

PLEASE DISCARD PREVIOUS DIVISIONAL PUBLICATIONS.

THIS BULLETIN REPLACES AND SUPERSEDES CORPORATE BULLETIN 135011.

SUBJECT: INFORMATION ON REAR CALIPER SERVICE PROCEDURE

MODELS: 1988-93 BUICK REGAL 1988-94 CHEVROLET LUMINA 1988-93 OLDSMOBILE CUTLASS SUPREME 1988-93 PONTIAC GRAND PRIX

SOME CASES HAVE BEEN REPORTED WHERE:

1. IT IS DIFFICULT TO R&R THE PARK BRAKE LEVER AND RETURN SPRING TO ALLOW RETRACTION OF THE PISTON WHEN SERVICING THE REAR CALIPERS.

2. IT IS DIFFICULT TO INSERT SLEEVES THROUGH NEW BOOTS WHEN REASSEMBLING THE CALIPERS.

TO ELIMINATE THESE DIFFICULTIES, SEVERAL TOOLS WERE INTRODUCED.

A. SLEEVE REMOVAL AND BORE REFINISH KIT B. PISTON RETRACTION TOOL C. SEAL INSTALLATION TOOL D. SANDING PAD AND DISC KIT (WITH THIS BULLETIN)

SERVICE PROCEDURE:

1. RAISE VEHICLE AND REMOVE REAR WHEELS AND TIRES.

2. REMOVE HYDRAULIC LINE BRACKET BOLT. IT IS NOT NECESSARY TO DISCONNECT HYDRAULIC LINE FROM THE CALIPER. (IT IS ALSO NOT NECESSARY TO REMOVE ANY OF THE PARK BRAKE CABLE OR LEVER ASSEMBLY WITH THE USE OF THIS NEW TOOL.)

3. REMOVE CALIPER MOUNTING BOLTS, AND REMOVE CALIPER AND SUPPORT.

4. REMOVE BRAKE PADS. CAREFULLY REMOVE THE INNER PADS TO PREVENT DAMAGE TO THE PAD RETAINERS.

A. PRY THE BOTTOM OF THE PAD OUT OF THE RETAINER CLIP. (SEE FIGURE 1.)

B. GENTLY TAP THE PAD DOWN AND OFF THE BRIDGE.

5. USE AN AIR HAMMER WITH KENT MOORE TOOL J-39495-1 TO REMOVE SLEEVES. WHEN USING THIS TOOL, IT IS NOT NECESSARY TO REMOVE THE BOOTS FIRST (SEE FIGURE 2). BY APPLYING CONSIDERABLE PRESSURE WITH THE AIR HAMMER AND TOOL, THE SLEEVES WILL BE DRIVEN RIGHT PAST THE BOOTS. HOLD THE CALIPER IN ONE HAND AND DRIVE THE SLEEVE AND BOOTS OUT. USE CARE NOT TO DROP THE SLEEVE AS IT IS PUSHED OUT, AND THEN REMOVE ANY REMAINING BOOT MATERIAL.

6. CLEAN CALIPER BRIDGE AND GROOVES ON BRIDGE WHERE THE INNER PAD GUIDES (USE 80 GRIT SANDING DISC, FILE. ETC).

7. CLEAN HOUSING BORES, GROOVES, AND BOLT SLEEVES WITH GM BRAKE PARTS CLEANER - P/N 12345754 (OR EQUIVALENT).

(A). GROOVES SHOULD BE FURTHER CLEANED WITH A WIRE BRUSH MOUNTED ON AN AIR/ELECTRIC DRILL MOTOR. USE KENT MOORE TOOL J-39495-3 (OR EQUIVALENT). AFTER THIS, USE A "SEAL PICK" OR A SMALL SCREWDRIVER TO SCRAPE ANY REMAINING SCALE FROM THE EDGES OF THE GROOVES. (SEE FIGURE 3).

(B). BORES SHOULD BE FURTHER CLEANED WITH A 7/8" FLEX HONE MOUNTED ON AN AIR/ELECTRIC DRILL MOTOR. USE KENT MOORE TOOL J-39495-2 (OR EQUIVALENT). USE BRAKE FLUID AS A HONING FLUID. DO NOT USE ANY PETROLEUM BASED FLUIDS- THEY ATTACK RUBBER USED ON THE CALIPER (SEE FIGURE 4).

NOTICE: AFTER BRUSHING AND HONING, THOROUGHLY FLUSH THE HOUSING BORES AND GROOVES WITH BRAKE PARTS CLEANER TO REMOVE ANY GRIT REMAINING. THE INBOARD GROOVES ARE NOT AS ACCESSIBLE FOR FLUSHING AS THE OUTBOARD GROOVES. EXTRA CARE MUST BE USED IN FLUSHING THESE AREAS COMPLETELY. WHEN FINISHED, WIPE WITH A CLEAN CLOTH OR PAPER TOWEL TO ASSURE NO GRIT REMAINS.

8. IT IS NOT NECESSARY TO REPLACE THE SLEEVES. THE SLEEVES HAVE A HARD CHROME SURFACE AND ARE EASILY CLEANED USING THE BRAKE PARTS CLEANER AND A RAG. WRAP A RAG AROUND THE SLEEVE AND SOAK THE RAG WITH BRAKE PARTS CLEANER. LET SOAK AND RUB THE OLD GREASE OFF THE SLEEVE. DO NOT USE ANY ABRASIVE MATERIALS TO CLEAN THE SLEEVES. SOME MINOR PITTING AND/OR WEAR MARKS MAY REMAIN. THIS IS OK! THEY WILL FILL UP WITH GREASE (SEE FIGURE 5).

NOTICE: ALL CONTAMINANTS MUST BE REMOVED FROM THE GROOVES IN THE CALIPER BORES TO INSURE PROPER FIT OF BOOT BEADS.

- SOME MINOR PITTING MAY REMAIN - THIS IS ACCEPTABLE.

9. THOROUGHLY LUBRICATE HOUSING GROOVES, BORES, SLEEVES, AND I.D. AND O.D. BEADS OF THE NEW BOOTS.

NOTICE: USE ALL OF THE GREASE FROM KIT. INSURE ALL GROOVES ARE FULL OF LUBE. IF ADDITIONAL LUBE IS NEEDED, USE GM P/N 18010909, OR EQUIVALENT SILICONE GREASE.

10. INSTALL LUBRICATED BOOT INTO INSIDE GROOVE IN CALIPER BORE.

11. MAKE SURE THE BOOT IS SEATED IN THE GROOVE BY PRESSING THE BEAD INTO THE GROOVE, AND ROTATE THE BEAD IN THE GROOVE TO INSURE THAT IT IS NOT ROLLED IN THE GROOVE.

12. POSITION THE NEW PLASTIC INSTALLATION CONE ON END OF SLEEVE. THE CONE IS INCLUDED IN ALL BOOT KITS (SEE FIGURE 6).

13. PUSH LUBRICATED SLEEVE IN FROM THE OUTSIDE OF CALIPER THROUGH I.D. OF INSTALLED BOOT UNTIL THE INSIDE END OF SLEEVE IS PAST THE GROOVE ON OUTSIDE OF CALIPER. REMOVE THE CONE FROM THE SLEEVE AND INSTALL IT ON THE OTHER END OF THE SLEEVE TO EASE INSTALLATION THRU THE OUTSIDE BOOT.

14. INSTALL LUBRICATED OUTSIDE BOOT - REFER TO STEP #11.

15. PUSH SLEEVE BACK THE OTHER WAY THROUGH THE 2ND BOOT, REMOVE THE CONE AND SEAT THE I.D. BEADS OF BOTH BOOTS INTO SLEEVE GROOVES. REPEAT FOR OTHER SLEEVE.

16. CYCLE EACH SLEEVE BACK AND FORTH IN CALIPER SEVERAL TIMES TO INSURE THAT NO PART OF THE BOOT IS PROTRUDING FROM THE GROOVE IN THE CALIPER BORE, AND THAT BOOT BEADS ARE SECURE IN SLEEVE GROOVES.

17. RETRACT CALIPER PISTON USING THE NEW KENT MOORE TOOL J-39730 ATTACHED TO KENT MOORE TOOL J-22269-01. AFTER RETRACTION, MAKE SURE THE GROOVES IN THE END OF THE PISTON ARE LINED UP IN A VERTICAL POSITION TO ACCEPT THE INNER PAD RETAINER (SEE FIGURE 7 AND 8).

A. RIGHT REAR CALIPER: TIGHTEN J-22269-01 AND ROTATE PISTON CLOCKWISE USING A 5/8" WRENCH ON THE HEX SECTION OF J-39730. EACH TIME J-39730 IS ROTATED, J-22269-01 MUST BE RETIGHTENED TO KEEP PRESSURE ON THE PISTON.

B. LEFT REAR CALIPER: USE SAME PROCEDURE AS (A) ABOVE, EXCEPT THAT J-39730 MUST BE ROTATED COUNTER CLOCKWISE.

NOTE: TO RETRACT THE CALIPER PISTON, CONTINUOUS PRESSURE MUST BE APPLIED ON THE PISTON USING J-22269-01.

18. REINSTALL THE INNER PAD RETAINER AND THE NEW BRAKE PADS. LUBRICATE CALIPER BRIDGE WITH A THIN FILM OF HI-TEMP GREASE. (3M* BRAKE LUBE/ANTI-SEIZE COMPOUND #08945 OR EQUIVALENT) SEE FIGURE 4 AND FIGURE 8.

19. IF THE ROTOR WAS REMOVED DURING CALIPER SERVICE, THE INNER HUB AND HUB FLANGE MUST BE CLEANED BEFORE REMOUNTING (SEE FIGURE 9). TO CLEAN THE CORROSION BUILD-UP ON THE ROTOR HUB, USE THE 80 GRIT SANDING DISC J-41013 (OR EQUIVALENT) ON AN AIR/ELECTRIC DRILL MOTOR.

NOTE: IT IS VERY IMPORTANT THAT THIS CLEANING PROCESS BE DONE ANY TIME THE ROTOR IS REMOVED FROM THE HUB. THIS IS A LEADING CAUSE OF ROTOR RUNOUT WHICH LEADS TO BRAKE PULSATION.

20. REINSTALL CALIPER - CARE MUST BE TAKEN TO PREVENT DAMAGE TO BOOTS ON KNUCKLE AND/OR ROTOR SURFACES. PUSH SLEEVES ALL THE WAY BACK FROM THE PADS. TORQUE BOLTS TO 125 N.M (92 LB. FT.).

21. REINSTALL HYDRAULIC LINE BRACKET AND BOLT.

22. CHECK PARK BRAKE CABLE OPERATION.

23. REINSTALL WHEELS AND TIRES - USE TORQUE STICK J39544-15 . (SEE FIGURE 10). WITH THE LAST PUBLICATION OF THIS BULLETIN, ALL DEALERS HAVE AT LEAST THE PROPER TORQUE STICK TO SERVICE W-CAR WHEEL NUTS.

WHEEL NUT TIGHTENING PROCEDURE:

A TORQUE WRENCH OR TORQUE STICK MUST BE USED TO INSURE THAT WHEEL NUTS ARE TIGHTENED TO SPECIFICATION. THIS SHOULD BE DONE IN TWO STEPS USING THE STAR PATTERN. FIRST, SNUG THE NUTS DOWN BY HAND. THEN, USING THE STAR PATTERN AND A TORQUE STICK/WRENCH, TIGHTEN THE WHEEL NUTS TO ABOUT HALF THE FINAL TORQUE. FINALLY, TIGHTEN THE WHEEL NUTS TO SPECIFICATION USING THE STAR PATTERN AND A TORQUE STICK/WRENCH. USE THE SAME AMOUNT OF IMPACT WRENCH OPERATING TIME AS WOULD NORMALLY BE USED WITHOUT A TORQUE STICK.

PART AVAILABILITY:

PART KITS: P/N 3494600 LUBRICANT AND BOOTS - 1 KIT - 2 CALIPERS

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

TOOL KIT: - KENT MOORE #J-39495 KIT*

KIT INCLUDES: A. PUNCH J-39495-1 B. HONE J-39495-2 C. WIRE BRUSH J-39495-3

KENT MOORE TOOL J-39730 - PISTON RETRACTOR TOOL** KENT MOORE TOOL J-22269-01 - ACCUMULATOR PISTON COMPRESSOR KENT MOORE TOOL J-39544-15 - (19MM 3/4") TORQUE STICK KENT MOORE TOOL J-41013 KIT KIT INCLUDES: A. ADAPTER: J-41013-1 B. 80 GRIT SANDING DISCS: J-41013-2

* EVERY DEALER RECEIVED THIS KIT FREE IN OCTOBER, 1991. ** EVERY DEALER RECEIVED THIS TOOL FREE IN MARCH, 1993.

NOTE: HONES AND WIRE BRUSHES WILL WEAR OUT. WHEN A NEW WIRE BRUSH IS FIRST USED, IT WILL NOT ENTER EASILY INTO THE BORE DURING USE. WHEN THE BRUSH WEARS ENOUGH THAT IT EASILY ENTERS THE BORE AND WON'T CLEAN THE GROOVES THOROUGHLY, IT SHOULD BE REPLACED.

WHEN A NEW HONE IS FIRST USED, THERE IS NOTICEABLE RESISTANCE WHEN TURNED THROUGH THE BORE. WHEN THIS RESISTANCE IS SLIGHT OR THE HONE BECOMES DAMAGED, THE HONE SHOULD BE REPLACED. REPLACEMENT WIRE BRUSHES, HONES, AND SANDING DISCS ARE AVAILABLE THROUGH THE KENT MOORE CORPORATION - 1-800-345-2233.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION NUMBER: T1755 LABOR TIME: 1.3 HOURS (NEW TIME - BOTH CALIPERS) MATERIAL ALLOWANCE: 2 SANDING DISCS PER VEHICLE

FIGURES: 10

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.

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