Is there any way to check a GT power brake booster while it is installed in the car ?
theogre
MAY 05, 06:28 PM
Yes.
How? Run engine, read Intake Vacuum on a gauge. Should be above ~ 20in @ idle. Vac Booster needs > ~ 17in to "recharge" because Booster is its own reserve tank. brakes should work w/ little effort. IF brakes are hard to push, have Vacuum problem or Booster lost 1 of 2 diaphragms. Or Brake System has major problems causing Hard Pedal.
Even has good reading on a gauge... 84-86 have Vacuum Filter on the engine bay that can get stuffed w/ crap. If people are autox racing etc and keep High Engine RPM for a long time then Booster will "run out" of vacuum and have "braking problems." Same problem as you push the pedal w/ engine off and pedal gets harder and harder to push after a few times.
If booster stops working instant you shut down... likely check valve is "dead." Can try cleaning it but avoid most chemicals including Brake Cleaners. All use same design but Vac Line is bigger for 87-88 Fiero and most parts stores don't have this.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
