INFO. ON SERVICEABILITY OF ABS AND ABS/TCS

REVISION: 03/13/85

THIS BULLETIN IS BEING REVISED TO CLARIFY PARTS INFORMATION. ARTWORK REMAINS THE SAME. PLEASE DISCARD BULLETIN 53-50-01 (SECTION 5 - BRAKES). *****************************************************************

SUBJECT: INFORMATION ON SERVICEABILITY OF ABS AND ABS/TCS PRESSURE MODULATOR VALVE (PMV) ASSEMBLY

MODELS: 1991-95 BUICK LESABRE, PARK AVENUE 1995 BUICK RIVIERA 1991-93 CADILLAC DEVILLE, FLEETWOOD, SIXTY SPECIAL 1991-95 OLDSMOBILE EIGHTY EIGHT, NINETY EIGHT 1995 OLDSMOBILE AURORA 1991-95 PONTIAC BONNEVILLE

THIS BULLETIN IS TO PROVIDE INFORMATION ON THE SERVICEABILITY OF THE PRESSURE MODULATOR VALVE (PMV) ASSEMBLY. SECTIONS 5E1 (ABS) AND 5E2 (ABS/TCS AND ABS) OF THE APPROPRIATE SERVICE MANUAL SHOULD ALSO BE UPDATED ACCORDINGLY.

AS OF FEBRUARY 9, 1995, PARTS WILL BE AVAILABLE THROUGH GMSPO THAT WILL ALLOW SERVICEABILITY OF THE PRESSURE MODULATOR VALVE (PMV) ASSEMBLY. CURRENTLY THE UNIT IS REPLACED AS A WHOLE ASSEMBLY. THIS BULLETIN IS TO INFORM THAT THE PMV WILL BE SPLIT INTO 2 UNITS: 1) THE VALVE BODY, AND 2) THE PUMP AND MOTOR ASSEMBLY, WHICH CAN THEN BE INDIVIDUALLY REPLACED.

PROCEDURE FOR DISASSEMBLING THE PMV ASSEMBLY:

(REFER TO FIGURE 1; (ABS ONLY SHOWN, ABS/TCS SIMILAR)

IMPORTANT: THE PRESSURE MODULATOR VALVE (PMV) ASSEMBLY MUST BE REMOVED BEFORE REPLACING THE VALVE BLOCK.

A CLEAN WORK AREA IS NEEDED TO PREVENT CONTAMINATION OF THE PMV ASSEMBLY AND ITS INTERNAL COMPONENTS.

REMOVE OR DISCONNECT:

1. PMV ASSEMBLY, REFER TO "PMV ASSEMBLY" IN SECTION 5E OF THE SERVICE MANUAL.

2. VALVE BLOCK-TO-PUMP ATTACHMENT BOLTS (3).

3. VALVE BLOCK FROM PUMP AND MOTOR ASSEMBLY.

INSTALL OR CONNECT:

1. METAL GASKET.

IMPORTANT: INSTALL NEW METAL GASKET ONLY AS SHOWN. FAILURE TO INSTALL THE METAL GASKET CORRECTLY WILL RESULT IN BRAKE FLUID LOSS AND/OR POOR BRAKE PERFORMANCE.

2. VALVE BLOCK TO PUMP AND MOTOR ASSEMBLY.

3. ATTACH BOLTS (3). TIGHTEN BOLTS TO 29 N.M (21 LB. FT.).

4. PMV ASSEMBLY, REFER TO "PMV ASSEMBLY" IN SECTION 5E OF THE SERVICE MANUAL.

THE FOLLOWING ATTACHMENTS (PMV SERVICEABILITY - BUICK, CADILLAC, OLDSMOBILE, AND PONTIAC) LIST BY DIVISION AND YEAR ALL OF THE TESTS, CHARTS OR DTC'S WHICH CURRENTLY STATE TO REPLACE THE PMV ASSEMBLY. AFTER THE TITLE OF EACH TEST, CHART, OR DTC IS THE NAME OF THE FAULTED UNIT WHICH IS TO BE REPLACED AS A RESULT OF THIS BULLETIN. FOR EXAMPLE, IN TEST B: PMV CONTINUITY TEST OF THE 1991 BUICK C/H, ALL AREAS WHERE IT STATES TO REPLACE THE PMV ASSEMBLY SHOULD NOW STATE "REPLACE THE VALVE BLOCK ONLY".

PARTS INFORMATION:

P/N DESCRIPTION === ===========

25642296 BRAKE PRESSURE MODULATOR VALVE KIT 1991-95 C/H AND G ABS ONLY

25642297 BRAKE PRESSURE MODULATOR VALVE KIT 1992-93 C/H ABS AND TCS

25642298 BRAKE PRESSURE MODULATOR VALVE KIT 1994-95 C/H AND G ABS AND TCS

25642299 BRAKE PRESSURE MODULATOR VALVE MOTOR KIT 1991-95 C/H AND G

25641270 BRAKE PRESSURE MODULATOR VALVE GASKET INCLUDED IN ALL OF THE ABOVE MENTIONED KITS

25641271 BOLT/SCREW - BRAKE PRESSURE MODULATOR VALVE 1991-95 C/H AND G

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION NUMBER: H2506 (MOTOR PACK - ABS REPLACE) H2517 (BLOCK, VALVE - ABS R&R OR REPLACE) REFER TO THE ATTACHED CHART FOR THE APPROPRIATE LABOR TIME.

FIGURES: 1 ATTACHMENTS: 5

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.

COPYRIGHT 1995 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.