One problem related to power assist hydraulic brake has been reported for the 2001 GMC Yukon. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2001 GMC Yukon based on all problems reported for the 2001 Yukon.
Lost steering and brakes. Shaft in pump snapped off inside housing. Towed to gm garage and new pump installed. Happened when backing and turning sharply over rough ground. Night. 70 degrees. Returned to campground using two hands on steering wheel and parking brake. On 4000 mile trip pulling 3 ton trailer. Waited 4 days for repair to be completed.