I dont see anything on AllData thats says GM will replace a complete PM. 87C13 was just for replacing the pressure switch. The G-bodies didn't get the proportioning valve replaced, only the B-body wagon. Here is a copy and paste of 87C13 from GM:
CAMPAIGN: POWERMASTER BRAKE SYSTEM/FAULTY PRESSURE SWITCH #87-C-13 - (Oct 5, 1990)
SUBJECT: POWERMASTER BRAKE SYSTEM
MODELS AFFECTED: 1985 REGAL 3.8L TURBO (ENGINE VIN CODE 9) AND RPO LM9 BRAKES 1986-87 REGAL 3.8L TURBO (ENGINE VIN CODE 7) 1986 LESABRE AND ELECTR ESTATE WAGON 1986 CHEVROLET CAPRICE STATION WAGON 1986 PONTIAC PARISIENNE WAGON 1986 OLDSMOBILE CUSTOM CRUISER STATION WAGON
TO: ALL CHEVROLET DEALERS
** SEE BOTTOM OF CAMPAIGN FOR INFORMATION CONCERNING OTHER ** AFFECTED DIVISIONS.
GENERAL MOTORS HAS DETERMINED THAT CERTAIN 1986 CHEVROLET "B" STATION WAGONS WITH POWERMASTER BRAKE SYSTEMS WERE BUILT WITH COMBINATION VALVES AND PRESSURE SWITCHES WHICH MAY BECOME FAULTY. IF LEFT UNCORRECTED THESE VEHICLES MAY EXPERIENCE A "HARD BRAKE PEDAL" OR "INCREASED BRAKE PEDAL TRAVEL". THESE CONDITIONS MAY BE CAUSED BY A CAST IRON COMBINATION VALVE ALLOWING AIR TO ENTER THE BRAKE SYSTEM OR BY A PRESSURE SWITCH LEAKING BRAKE FLUID.
TO PREVENT EITHER OF THE ABOVE CONDITIONS FROM OCCURING, VEHICLES WILL BE INSPECTED AND THOSE EQUIPPED WITH THE CAST IRON COMBINATION VALVE WILL RECEIVE A NEW BRASS COMBINATION VALVE. ALSO, PRESSURE SWITCHES WILL BE INSPECTED AND REPLACED IF NECESSARY.
VEHICLES INVOLVED
INVOLVED ARE CERTAIN 1986 CHEVROLET "B" STATION WAGONS WITH POWERMASTER BRAKE SYSTEMS BUILT WITHIN THE FOLLOWING VIN BREAKPOINTS:
YEAR MODEL PLANT FROM THROUGH
1986 "B" WAGON FAIRFAX GX100001 GX207019
INVOLVED VEHICLES HAVE BEEN IDENTIFIED BY VIN COMPUTER LISTINGS. COMPUTER LISTINGS CONTAIN THE COMPLETE VIN, OWNER NAME AND ADDRESS DATA, AND ARE FURNISHED TO INVOLVED DEALERS WITH THE CAMPAIGN BULLETIN. OWNER NAME AND ADDRESS DATA FURNISHED WILL ENABLE DEALERS TO FOLLOW-UP WITH OWNERS INVOLVED IN THIS CAMPAIGN.
THESE LISTINGS MAY CONTAIN OWNER NAMES AND ADDRESSES OBTAINED FROM STATE MOTOR VEHICLE REGISTRATION RECORDS. THE USE OF SUCH MOTOR VEHICLE REGISTRATION DATA FOR ANY OTHER PURPOSE IS A VIOLATION OF LAW IN SEVERAL STATES. ACCORDINGLY, YOU ARE URGED TO LIMIT THE USE OF THIS LISTING TO THE FOLLOW-UP NECESSARY TO COMPLETE THIS CAMPAIGN. ANY DEALER NOT RECEIVING A COMPUTER LISTING WITH THE CAMPAIGN BULLETIN HAS NO INVOLVED VEHICLES CURRENTLY ASSIGNED.
OWNER NOTIFICATION
OWNERS WILL BE NOTIFIED OF THIS CAMPAIGN ON THEIR VEHICLES BY CHEVROLET MOTOR DIVISION (SEE COPY OF OWNER LETTER INCLUDED WITH THIS BULLETIN).
DEALER CAMPAIGN RESPONSIBILITY
DEALERS ARE TO SERVICE ALL VEHICLES SUBJECT TO THIS CAMPAIGN AT NO CHARGE TO OWNERS, REGARDLESS OF MILEAGE, AGE OF VEHICLE, OR OWNERSHIP, FROM THIS TIME FORWARD.
WHENEVER A VEHICLE SUBJECT TO THIS CAMPAIGN IS TAKEN INTO YOUR NEW OR USED VEHICLE INVENTORY, OR IT IS IN YOUR DEALERSHIP FOR SERVICE IN THE FUTURE, YOU SHOULD TAKE THE STEPS NECESSARY TO BE SURE THE CAMPAIGN CORRECTION HAS BEEN MADE BEFORE RESELLING OR RELEASING THE VEHICLE.
OWNERS OF VEHICLES RECENTLY SOLD FROM YOUR NEW VEHICLE INVENTORY ARE TO BE CONTACTED BY THE DEALER, AND ARRANGEMENTS MADE TO MAKE THE REQUIRED CORRECTION ACCORDING TO INSTRUCTIONS CONTAINED IN THIS BULLETIN.
PARTS INFORMATION
PARTS REQUIRED TO COMPLETE THIS CAMPAIGN ARE TO BE OBTAINED FROM GMSPO. TO ENSURE THESE PARTS WILL BE OBTAINED AS SOON AS POSSIBLE, THEY SHOULD BE ORDERED FROM GMSPO ON A "C.I.O." ORDER WITH NO SPECIAL INSTRUCTION CODE, BUT ON AN ADVISE CODE 2.
QUANTITY/ PART NUMBER DESCRIPTION VEHICLE
25509419 BRASS COMBINATION VALVE 1
18018141 PRESSURE SWITCH (INCLUDES O-RING) 1
SERVICE PROCEDURE
1. INSPECT PRESSURE SWITCH. IF THE CURRENT PRESSURE SWITCH IS GRAY, MOVE ON TO STEP 2. IF THE CURRENT SWITCH IS BLACK, REMOVE AND REPLACE PRESSURE SWITCH ACCORDING TO THE PROCEDURE BELOW AND THEN MOVE ON TO STEP 2.
A. DEPRESSURIZE POWERMASTER UNIT BY TURNING IGNITION "OFF", AND APPLY AND RELEASE BRAKE PEDAL A MINIMUM OF TEN (10) TIMES USING APPROXIMATELY FIFTY (50) POUNDS OF FORCE ON PEDAL TO FULLY DEPLETE THE POWER ASSIST.
NOTICE: FAILURE TO FULLY DEPRESSURIZE POWERMASTER UNIT COULD RESULT IN BRAKE FLUID BEING SPRAYED ON SERVICE PERSONNEL AND COULD CAUSE DAMAGE TO PAINTED SURFACES.
B. DISCONNECT 3-WIRE ELECTRICAL CONNECTOR (FIG. 1, 40) FROM PRESSURE SWITCH (FIG. 1, 1).
C. REMOVE OLD PRESSURE SWITCH (FIG. 1, 1).
D. LUBRICATE NEW O-RING (FIG. 1, 2) WITH CLEAN, FRESH BRAKE FLUID AND INSTALL ON NEW PRESSURE SWITCH.
E. INSTALL NEW PRESSURE SWITCH (FIG. 1, 1), TIGHTEN TO 20-27 NM (15-20 LB. FT.).
NOTICE: TORQUE VALUES SPECIFIED ARE FOR DRY, UNLUBRICATED FASTENERS.
F. RECONNECT 3-WIRE ELECTRICAL CONNECTOR (FIG. 1, 40) TO PRESSURE SWITCH (FIG. 1, 1). BE SURE ELECTRICAL CONNECTOR IS SECURELY SEATED.
2. LOCATE COMBINATION VALVE (ON FRAME RAIL BELOW MASTER CYLINDER). IF THE CURRENT COMBINATION VALVE IS THE POTENTIALLY FAULTY CAST IRON VALVE TYPE THE VALVE MUST BE REPLACED WITH A BRASS VALVE TYPE BY FOLLOWING THE PROCEDURE BELOW. IF THE VEHICLE ALREADY HAS THE BRASS VALVE, THE COMBINATION VALVE DOES NOT NEED TO BE REPLACED. PROCEED TO STEP 3. FIGURE 2 ON THE NEXT PAGE ILLUSTRATES THE DIFFERENCES IN THE TWO VALVE TYPES.
A. REMOVE THE ELECTRICAL WARNING HARNESS CONNECTOR FROM THE PRESSURE DIFFERENTIAL SWITCH BY SQUEEZING THE ELIPTICAL-SHAPED PLASTIC LOCK RING AND PULLING UP. A PAIR OF PLIERS MAY AID IN REMOVING THE CONNECTOR.
B. DISCONNECT HYDRAULIC LINES AT COMBINATION VALVE. PLUG LINES TO PREVENT LOSS OF FLUID AND ENTRANCE OF DIRT.
C. REMOVE POTENTIALLY FAULTY CAST IRON COMBINATION VALVE.
D. INSTALL BRASS COMBINATION VALVE. TORQUE MOUNTING BOLTS TO 20 NM (14 LB. FT.).
E. CONNECT WARNING HARNESS SWITCH TO VALVE SWITCH TERMINAL.
F. REMOVE PLUGS AND CONNECT HYDRAULIC LINES AT COMBINATION VALVE. TORQUE LINES TO 24 NM (18 LB. FT.).
G. CONNECT ELECTRICAL WARNING HARNESS CONNECTOR TO PRESSURE CONTROL DIFFERENTIAL SWITCH.
H. BLEED ENTIRE BRAKE SYSTEM. DO NOT MOVE VEHICLE UNTIL A FIRM BRAKE PEDAL IS OBTAINED.
I. CHECK BRAKE LINES FOR PROPER CLEARANCES.
3. INSTALL CAMPAIGN IDENTIFICATION LABEL.
CAMPAIGN IDENTIFICATION LABEL
EACH VEHICLE CORRECTED IN ACCORDANCE WITH THE INSTRUCTIONS OUTLINED IN THIS PRODUCT CAMPAIGN BULLETIN WILL REQUIRE A "CAMPAIGN IDENTIFICATION LABEL." EACH LABEL PROVIDES A SPACE TO INCLUDE THE FIVE (5) DIGIT DEALER CODE OF THE DEALER PERFORMING THE CAMPAIGN SERVICE. THIS INFORMATION MAY BE INSERTED WITH A TYPEWRITER OR A BALL POINT PEN.
EACH "CAMPAIGN IDENTIFICATION LABEL" IS TO BE LOCATED ON THE RADIATOR CORE SUPPORT IN AN AREA WHICH WILL BE VISIBLE WHEN THE VEHICLE IS BROUGHT IN FOR PERIODIC SERVICING BY THE OWNER.
APPLY "CAMPAIGN IDENTIFICATION LABEL" ONLY ON A CLEAN DRY SURFACE.
CLAIM INFORMATION