Brakes - Increased Pedal Travel/Brass Combination Valve

9222buick01

Bulletin
86-5-9

Date
Jan., '89

Ref. No.
86-220-5

Corp. Ref. No.
705004R


SUBJECT:
INCREASED PEDAL TRAVEL - POWERMASTER


MODELS AFFECTED:
1986 ELECTRA/LESABRE ESTATE WAGONS


This bulletin has been revised to specify 'brass' valve for Part Number 25509419 and clarify this brass valve is the only type now available; added a sentence under 'Diagnosis of Condition' regarding cast iron combination valves.

DIAGNOSIS OF CONDITION

Some 1986 Electra/Estate 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 Part Number 25509419 to prevent recurrence of the condition (this brass valve is the only type now available from GMSPO). The entire brake system should be rebled, 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 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.