apache

I was talking with my neighbor and he had told me his vac pump went south long ago on his 94 and he converted his brakes to Hydroboost. Hows this work? I know GMC uses this on their gas trucks, but I can pitcure the set up.??

rockwithjason

The hydroboost uses oil pumped from the power steering pump to operate the power assist unit for the master cylinder. This conversion has been done many times. You will have to find a hydroboost unit that will work on the truck and make up the pressure and return lines for the ps pump.

infidel

Only problem with changing over to hydroboost because the vacuum pump is bad is that the brake boost isn't the only thing that operates off vacuum.
Without a funtioning vacuum pump you will lose the HVAC controls and 4wd.

apache

Have to ask him on that one reagrding the heater controls. Its a 2wd. Does the oil from the pump turn a vac pump on the hydro set up? I remember on our old 85 GMC the unit was part of the steering column I think??

rockwithjason

No, hydroboost is all hydraulic, no vacuum at all. The unit bolts in place of the vacuum booster on the engine side of the fire wall.