Power Master Brakes - Increased Pedal Travel
89oldsmobile02SUBJECT: INCREASED PEDAL TRAVEL - POWERMASTER, (BLEED SYSTEM, REPLACE COMBINATION VALVE)
MODELS/YEARS: 1986 CUSTOM CRUISER WAGON
NUMBER: 86-T-6B
CORP. REF. NO: 705004R
DATE: February 1989
SECTION: 5, 5D4
This bulletin supersedes Dealer Technical Bulletin 86-T-6A, date 6/19/87 which may be discarded.
DIAGNOSIS OF CONDITION:
Some 1986 Custom Cruiser Wagons may experience increased pedal travel at higher mileage/extended use. This may be the result of air ingestion at the combination valve and traveling to the left front caliper.
In order to diagnose this condition, bleed the left front brake assembly. If this results in less pedal travel, the combination valve should be replaced with brass valve P/N 25509419 to prevent reoccurrence of the condition (this brass valve is the only type now available from GMSPO). The entire brake system should be re-bled, and master cylinder fittings checked for proper torque. If the pedal travel is still long and no air is found after the initial bleed, refer to the Service Manual for the servicing procedure.
Any cast iron combination valve in dealer stock may be used on other applications.
ADDITIONAL SERVICE INFORMATION:
Some dealers are still replacing the whole Powermaster unit instead of using the appropriate service kits available for the Powermaster assembly. Proper diagnosis per the Service Manual will indicate the correct kit to use.
The following repair kits have been released to assist in servicing the Powermaster brake units. The labor times indicated include time for the functional system check and diagnostic procedure.
LABOR OPERATION LABOR TIME
PART NUMBER DESCRIPTION NUMBER NUMBER
18011279 Pump and Motor Asm. Pkg. H0980 .8
18014977 Pressure Switch Asm. Pkg. H0778 .4
18014978 Accumulator Asm. Pkg. H0985 .3
18013293 Reservoir Cover Asm. Pkg. H0610 .2
18011398 Boot Pkg. T1377 .4
18010875 Bracket Pkg. T1378 1.1
18011403 Sump Hose Pkg. H0745 .3
Parts are currently available from GMSPO.