Normal Hydroboost Noise Characteristics, Normal Operating

Noises

Normal Hydro-boost brake units will produce certain characteristic booster noises. these noises occur, for the most part, when the brake pedal is manipulated in a manner not associated with everyday braking or driving habits. the general catagories of normal operating noises are (1) hissing noises and (2) clunk/click/clatter noises.

The Hydro-boost will emit normal hissing noises when above normal brake pedal efforts are applied (40 lbs. pedal effort and up). The hiss sounds are particularly noticeable with the vehicle motionless and will increase in intensity as pedal pressure increases above 40 lbs. and system operating temperature increases. Loud hissing sounds at or below normal (20-25 lbs.) pedal effort warrants investigation.

Clunk, clatter or clicking noises will be heard when the brake pedal is quickly released from hard (50-100 lbs.) pedal efforts.