Two problems related to power assist brake have been reported for the 1997 GMC Sierra. The most recently reported issues are listed below.
Booster failed while traveling interstate. This was a class 9 systems failure (loss of power) without warning. Failure was a result of a split diaphram.
The consumer state's there is a leakage within the hydro- booster and the master cylinder which causes while driving at any speed and applying the brakes, the vehicle is pulling to the right. Ak.