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

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.

Problem Data
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Average mileage: 183,851 (87,000–291,000)
16 model years affected: 1990, 1991, 1992, 1993, more1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
34 people reported this problem
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Viewing 1 - 11 of 11 comments
Always low on power steering fluid. Found fluid dripping from between the hydro boost and master cylinder. Never had problems with the brake fluid being low.
Brankes and steering both quit at the same time. I am assuming that it is something to do with the combined system.
its been a ongoing problem and i cannot see m to find this part cheaper then 300 dollars
rear brakes failed,leak from hydro-boost,not repaired
Leaking power steering fluid where the master cylinder and the hydroboos go together.
This cause me an accident in the rain and a 500.00 ticket, insurance being sued and a point on my record and insurance costs raised, and possible deadly situation.
Powersteering fluid leaking like blood
leak a bit for a while, than suddenly sprays all over under battery comp.
Leaking power steering fluid between master cylinder and booster when brake is depressed.
my GMC Safari van has erattic operation of antilock brakes and pedal slowly drifts to the floor wgen at a a stop light not losing brake fluid replaced master cylinder with no improvement
First I had to replace the line from booster to steering box @ 150,000 miles. Then it started losing power steering fluid just recently. However I needed to change my rear axle and worked on that and keep filling the power steering. Went thru a gallon of power steering fluid and then started having issues with my speed sensors. Erratic speedometer readings and downshifting while driving. Then not shifting because speedometer was not accurately seeing my speed. I thought the power steering fluid leaking was causing the speed sensor issues by getting on the sensors or shorting out the wiring. I took of the rotors to see how much power steering fluid was on the sensors. Saw my rear rotor seal was damaged and grease was all over the sensor on the driver side. I replaced the bearings and races and seal on both rotors. Still had speed sensor issues. ABS light comes on. Was going to replace the line from the booster to the pump. Then saw where the leak was coming from. It leaks right between the booster and the brake master cylinder. Hope replacing it will solve the speed sensor issue. Could have2 separate issues?