POWERMASTER BRAKE ASSEMBLY EXCHANGE PROGRAM

1986 PARISIENNE WAGON

Seal kits and component parts will not be available to dealers to service the 1986 Powermaster Brake Assembly.

If a Powermaster Unit or any of its components require repair or replacement, an assembly is available from WDDGM on their Parts Exchange Plan under the following part number:

Exchange Unit Vehicle Usage Part Number ------------- ----------- Parisienne 18013682

The Powermaster Assembly Package from WDDGM will contain the following items:

1 - Powermaster Assembly (Items 17 and 44 shown in Figure 1) 1 - Pre-addressed return shipping label *1 - Information Data Sheet 1 - Instruction Sheet

*A copy of this data sheet is included with this bulletin.

IT IS IMPORTANT THAT FUNCTIONAL TEST RESULTS BE RECORDED PRIOR TO REMOVAL OF THE ORIGINAL POWERMASTER ASSEMBLY FROM A VEHICLE SO THAT THE FUNCTIONAL TEST RESULTS CAN BE LISTED ON THE DATA SHEET WHEN IT IS RETURNED WITH THE REPLACED UNIT.

The replaced (original) Powermaster Unit is to be carefully packaged in the container the new unit was received; data sheet completely filled out, and enclosed with the unit.

Refer to the Parts Exchange Plan on page E-1 in the current WDDGM Dealer Parts and Accessories Price Schedule for complete instructions when returning the part to insure you will receive your exchange credit.

PRELIMINARY EVALUATION TO DETERMINE NEED FOR EXCHANGE

The following outline indicates preliminary checks required to diagnose a Powermaster to determine the need for an exchange unit.

IF THE POWERMASTER PUMP RESERVOIR FLUID LEVEL CHECKING PROCEDURE IS NOT FOLLOWED, THE RESERVOIR MAY BE OVERFILLED. ANY OVERFILLED PUMP RESERVOIR WILL CAUSE FLUID TO LEAK OUT OF THE VENTS AND COULD RESULT IN AN INCORRECT DIAGNOSIS OF A LEAK.

A. Check the pump reservoir fluid level using the following procedures:

1. Turn ignition switch off.

2. Apply medium force to the brake pedal ten (10) times.

Step 2 is required to allow the brake fluid in the accumulator to return to the reservoir prior to checking for correct level.

3. Clean reservoir cover of all dirt.

4. Remove reservoir cover and check fluid level. Refer to Figure 2.

a. Fluid level in both sides of reservoir should be between the maximum and minimum indicator marks.

b. If fluid level is low, fill to "full" mark(s) with only clean new brake fluid meeting DOT 3 specifications.

B. Verify electrical power to the Powermaster Unit and the presence of proper ground circuits. Refer to Figure 3.

C. Install J-35126 test gage adapter and perform 1986 Parisienne Service Manual Functional Check and Diagnostic Procedure (Section 5B).

The acceptable value for the Functional Check are:

Time to charge from 0 psi to:

Pump switch "off" - 20 seconds max. - Sequence #1

Pump switch "off" pressure - 635 to 735 psi (4.378-5.068 kPa) - Sequence #2

Pump switch "on" pressure - 490 to 530 psi (3.378-3.654 kPa) - Sequence #3

1-PUSHROD 9-FLUID LEVEL INDICATOR FOR 2-ELECTRICAL CONNECTOR PUMP RESERVOIR. SEE VIEW A 3-ELECTRICAL CONNECTOR 10-MASTER CYLINDER RESERVOIR 4-BRAKE PIPE (OUTBOARD) 5-NUT 11-FLUID LEVEL INDICATOR FOR 6-POWERMASTER UNIT (EXCHANGE) MASTER CYLINDER. SEE VIEW A 7-MOUNTING BRACKET 12-HIGH FLUID LEVELS 8-PUMP RESERVOIR (INBOARD) 13-LOW FLUID LEVELS

Time between pump cycles with:

"Steady brake apply and hold" - 30 seconds min. - Sequence #4

WARNING

Switch "on" pressure - 355 to 435 psi (2.448-2.999 kPa)- Sequence #5

*Accumulator precharge pressure - 200 to 330 psi (1.379-2.275 kPa)- Sequence #6

Time to charge between Pump switch "on/off" - 10 seconds max. (Sequence #8)

*Fluid temperature in accumulator at 60-80 DEG F (16-27 DEG C) .

If functional check procedures do not at this time show cause for unit removal, continue diagnosis for leaks, poor brake bleed, poor brake adjustment, pump noise (excessive). Adjust and repair all faults external to Powermaster before installing an exchange unit.

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.