Power Brake Booster Check Valve - Rattle
Bulletin: 86-5-2Date: Nov, '85
Ref. No..: 86-038-5
SUBJECT: POWER BRAKE BOOSTER CHECK VALVE RATTLE
MODELS AFFECTED: 1986 CENTURYS
The power brake vacuum supply system on the 1986 Centurys equipped with a 2.5L (LR8) engine uses larger vacuum hoses and fittings than previous model years. This feature allows quicker vacuum booster response. Production cars that have been evaluated may exhibit a rattling noise caused by the fluttering of the vacuum booster check valve. This noise is apparent after the brake pedal has been released while the engine is running.
This condition can be confirmed by placing your hand on the check valve (located on the vacuum booster) while someone pumps the brake pedal. As the check valve flutters, a vibration will be felt. Production since September 13, 1985 used a revised check valve to eliminate this condition. The service check valve kit, part number 18012017 contains a revised valve. The check valve in the kit should be used to correct the above condition.