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GMC Yukon Denali Problems

Power Brake Units May Leak Fluid From Hydro-Boost Unit on GMC Yukon Denali

Problem Description and Possible Solution

Power brake systems using "hydro-boost" may leak power steering fluid from the hydro-boost unit located behind the brake master cylinder. Replacement of the hydro-boost unit is the common repair to correct this concern.

(19 people reported this problem)

GMC Yukon Denali Vehicles With This Problem

RepairPal Verified
Average mileage: 146,555 (94,000–229,000)
8 model years affected: 1999, 2000, 2002, 2003, more2004, 2005, 2006, 2007
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Viewing 1-7 of 7 comments
hydroboost failure was triggering the Service Immediately lights and applying the brakes. replaced hydroboost for around $900 and it fixed it.
Thought the PS pump was leaking - replaced in my drive. Still had a hard to find leak. Took to good honest shop - diagnosed as the hydrobooster. Waiting on estimate now. See the part is available at O'reilly for about $106 - rebuilt. No sure this is a 'repair in my driveway' type of thing I could do. $584 with labor.
Once the breech occurred, almost impossible to make right turns and braking is EXTREMELY difficult.