Four problems related to brake master cylinder have been reported for the 1998 GMC Sierra. The most recently reported issues are listed below.
Master cylinder failed causing the brake pedal to go to the floor. Nlm.
Initial problem 09/02/98 was both rear axle seals leaking causing brakes to fade. Again on 11/04/98 rear axle seals leaking, adjusted brakes. 11/06/98 brakes locking-up. 11/13/98 brakes grabbing, replaced both rear brake shoes, abs light on-module not activating brake release-replaced anti-lock brake module-master cyl bypassing-replaced master cyl. 01/20/99 abs light comes on-brake peddle hard to push-replaced abs brake valve. 03/23/99 brakes failed to slow vehicle-involved in accident-replaced abs pressure modulating valve.
The consumer has been experiencing problems with windshield wiper motor. When turning the windsheild wipers on, the motor makes a lot of noise. The manufacturer has yet to be contacted. Vehicle also has the following problems: engine coolant tank and brake master cylinder are leaking, brakes and fuel pump are noisy, and passenger side defroster does not flow enough air.
When brake pedal was applied it went straight to the floor, resulting in extended stopping distance. Dealer replaced the master cylinder, but that did not solve the problem.