Hydroboost Vs Vacuum Vs Powermaster
Vacuum boosters need vacuum to work. There is very little on a 231 ci engine with an overdrive, fuel inj, and a turbo. The hydroboost was designed and built by Bendix Aviation Corp., who sold it to Bosch in 1995. The G.N.'s have, part for part, the same brakes as an S10 p.u. There is a big weight difference, a big horsepower difference, and a big speed difference. The T Types from 83-85 used the Hydroboost from the factory. Those hydroboosts are still running trouble free 25 years later. G.M. is always partial to A.C. Delco as a supplier. Delco saw the smog dog 4 cyls and fuel shortage cars on the horizon, and knew that vacuum was going to be a problem. They developed the Powermaster as a complete "module" type bolt on brake system, for heavy station wagons and for the turbo charges cars, for the 86 model year. It's a great idea, but pumping brake fluid at high pressure isn't. Brake fluid is not a lubricant. The vanes in the P/M pump were made of phenolic resins, not steel. The steel vanes would gall with brake fluid as a lubricant. So, the phenolic vanes wear out quickly, trying to pump high pressure. The other problem is the seal between the pump and it's windings. When the seal goes out, the 12v section floods with brake fluid, and shorts out the fuses and the motor. No motor, no pressure=hard brake pedal. The S10 used the same vac booster as the std Regal, but no turbo. G.M ceased using the Powermaster in 1987. Most cars turned into FWD's after that. Luckily, the new Hydroboosts can be fitted onto the G bodies, with no alterations, to replace the Powermaster. The hydroboost offers superior stopping power, with no vacuum involved, and no electric motors involved. They can deliver up to 2000psi to the calipers, at idle p/s pump speed. They can even outlast the car.
