Two problems related to power assist brake have been reported for the 2004 GMC Sierra. The most recently reported issues are listed below.
While applying the brakes the pedal went to floor. Driver noticed that the pedal was hard, and vehicle would stop on its own. Driver took vehicle to the dealer for inspection, and mechanic determined that disc brakes and power booster needed to be replaced.
Crash: 1) traveling on interstate at 55-60 mph 2) poor braking ability to stop vehicle during panic stop.