Power Brake Booster Help
Thread Starter
Intermediate
Joined: Feb 2012
Posts: 42
Likes: 0
Power Brake Booster Help
Any help would be greatly appreciated! Happy Fourth of July!!!
I believe my Booster is not working. Brakes have been bled, reservoir is full. Brakes work but not well. I believe I only have manual brakes since it requires a lot of effort and it is not possible to lock the brakes with foot pressure
1977
Manual Transmission
New 383 Stroker
Edlebrock 750
New engine just installed. Power brake booster vacuum line connected to back side of Carb using factory connection. Booster disassembled during rebuild but NOT rebuilt.
Could it be a vacuum issue? If so, how do I check?
Should I get a new factor booster or hydro booster?
Jerry
I believe my Booster is not working. Brakes have been bled, reservoir is full. Brakes work but not well. I believe I only have manual brakes since it requires a lot of effort and it is not possible to lock the brakes with foot pressure
1977
Manual Transmission
New 383 Stroker
Edlebrock 750
New engine just installed. Power brake booster vacuum line connected to back side of Carb using factory connection. Booster disassembled during rebuild but NOT rebuilt.
Could it be a vacuum issue? If so, how do I check?
Should I get a new factor booster or hydro booster?
Jerry
Drifting
Joined: May 2008
Posts: 1,647
Likes: 5
From: Roseville CA
I'm about to change the booster in my 71 today. There's a few ways to check.
Check the check valve. Not sure how to test it. Might be easy to buy a new one.
With the engine off, press down on the brakes and start the engine. The pedal should move down further if it's working.
After running the engine for a few minutes, shut it off. You should get a couple of full boost presses and then the pedal will get hard.
Some have said you can listen near the booster and hear hissing if it's leaking.
If you pitch off the booster vacuum hose while the engine is running, it should change the idle speed, if it's leaking bad.
If you have a might vac, you can test to see if it holds vacuum. I did this test on mine and it could never build any vacuum. I bought a rebuild booster and it would start building vacuum after 15 pumps on the might vac.
Check the check valve. Not sure how to test it. Might be easy to buy a new one.
With the engine off, press down on the brakes and start the engine. The pedal should move down further if it's working.
After running the engine for a few minutes, shut it off. You should get a couple of full boost presses and then the pedal will get hard.
Some have said you can listen near the booster and hear hissing if it's leaking.
If you pitch off the booster vacuum hose while the engine is running, it should change the idle speed, if it's leaking bad.
If you have a might vac, you can test to see if it holds vacuum. I did this test on mine and it could never build any vacuum. I bought a rebuild booster and it would start building vacuum after 15 pumps on the might vac.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
IF you want a solid pedal that has about 2" of travel to stop the car, and will not sag to the floor with a heavy foot, get a Hydrobooster.....
every GM car I have ever driven....over 1/2 a century now, has that saggy baggy pedal, except the HB equipped ones....Sharks suffer more than average from saggy assed brakes....
I tried every trick in the book to get the brakes to feel right, and so doing the HB on a direct A-B change out without touching the brake lines, gave me a GREAT pedal....
every GM car I have ever driven....over 1/2 a century now, has that saggy baggy pedal, except the HB equipped ones....Sharks suffer more than average from saggy assed brakes....
I tried every trick in the book to get the brakes to feel right, and so doing the HB on a direct A-B change out without touching the brake lines, gave me a GREAT pedal....
Thread Starter
Intermediate
Joined: Feb 2012
Posts: 42
Likes: 0
I'm about to change the booster in my 71 today. There's a few ways to check.
Check the check valve. Not sure how to test it. Might be easy to buy a new one.
With the engine off, press down on the brakes and start the engine. The pedal should move down further if it's working.
After running the engine for a few minutes, shut it off. You should get a couple of full boost presses and then the pedal will get hard.
Some have said you can listen near the booster and hear hissing if it's leaking.
If you pitch off the booster vacuum hose while the engine is running, it should change the idle speed, if it's leaking bad.
If you have a might vac, you can test to see if it holds vacuum. I did this test on mine and it could never build any vacuum. I bought a rebuild booster and it would start building vacuum after 15 pumps on the might vac.
Check the check valve. Not sure how to test it. Might be easy to buy a new one.
With the engine off, press down on the brakes and start the engine. The pedal should move down further if it's working.
After running the engine for a few minutes, shut it off. You should get a couple of full boost presses and then the pedal will get hard.
Some have said you can listen near the booster and hear hissing if it's leaking.
If you pitch off the booster vacuum hose while the engine is running, it should change the idle speed, if it's leaking bad.
If you have a might vac, you can test to see if it holds vacuum. I did this test on mine and it could never build any vacuum. I bought a rebuild booster and it would start building vacuum after 15 pumps on the might vac.
Taking mine off now. 3 bolts down and 1 to go. The bad news, I cant even see the 4th! How did you get in there?
Drifting
Joined: May 2008
Posts: 1,647
Likes: 5
From: Roseville CA
I now have amazing brakes though. Helpfully yours turns out well.
Racer
Joined: Sep 2007
Posts: 288
Likes: 1
It has been a long time since I did this. I used a universal U joint to get at the tight angles with long extension to get some turning room with the ratchet. Socket U joint extension U joint extension ratchet. Be sure to use some tape around the upper U joint you don't want to much wobble. Going back put some tape in the socket to hold the nut in the socket. If you can't see the nut just visualize where the nut is. Good luck
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Thread Starter
Intermediate
Joined: Feb 2012
Posts: 42
Likes: 0
It has been a long time since I did this. I used a universal U joint to get at the tight angles with long extension to get some turning room with the ratchet. Socket U joint extension U joint extension ratchet. Be sure to use some tape around the upper U joint you don't want to much wobble. Going back put some tape in the socket to hold the nut in the socket. If you can't see the nut just visualize where the nut is. Good luck
Now I have to figure out where all the lights go that fell out of their spots on the speedometer and tach......UPDATE Color of wires are stamped on back of TACH and Speedometer...TOO FUNNY!
This is a frustrating job.
Last edited by jwbwx1; Jul 8, 2012 at 05:17 PM.