Power Booster
Thread Starter
Instructor
Joined: Mar 2003
Posts: 162
Likes: 0
From: Niagara Falls Ontario
Power Booster
Can anyone tell me how to check a power booster, or what the signs are for a bad one. I just bought a 82 pontiac fire bird trans am and there is a funny hissing sound coming from there when the brakes are applied and the brakes are a little spondy. :crazy:
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Re: Power Booster (74BBcherryred)
That is definitely a sign. You should run the engine, then shut it off. With the engine off press the brake a couple of times and it should assist the first time, maybe the second and then get hard.
Instructor
Joined: Jun 2001
Posts: 116
Likes: 0
From: Brighton MI
Re: Power Booster (74BBcherryred)
If the Booster is leaking then the engine has a vacuum leak. With the car running, pinch the hose going to the booster off with a a pair of vice grips and see if the idle changes. If it does you have a leaking booster and it needs to be replaced. Good luck
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Power Booster (74BBcherryred)
The booster should hold a vacuum charge for an extended period of time. For example ive pulled the hose connection from the booster in cars that have not been run for days and can hear the whoosh and hissing as air rushes in to fill the void. So check it like this. First start the car so vacuum is applied to the booster. Shut it off and wait a few hours and pull the hose and listen for the air rushing in. If you dont hear it its bad. A good booster will hold vacuum for days on end. In worst case a bad one wont hold vacuum at all.
Instructor
Joined: Apr 2003
Posts: 159
Likes: 0
From: Melville NY
Re: Power Booster (74BBcherryred)
Another easy way of testing the power booster ( as per GM manual) is: 1) turn engine off wait for one minute. 2) press on brake pedal and hold down. 3) while holding down brake pedal start the engine at this point if the power booster is ok you will feel the pedal go down, if the pedal does not go down then the booster is shot.
