brake booster
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
brake booster
well, it's either my master clynder or brake booster.... my brake lines are all aired out and i still have the sponge pedal....so i figure i mine as well get a new m.c. but should i change my booster also... how hard is it the switch out the whole setup m.c. and booster?
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Intermediate
Joined: Jul 2004
Posts: 42
Likes: 0
From: NY
Someone will correct me if I'm wrong, but if the booster is bad, I don't think you would have a spongy pedal, you would have a rock hard pedal. And from what I hear, the booster is a real pain to change. The nuts are up under the dash, on the other side of the firewall behind the booster.
Are you sure you got all the air out? I just replaced my MC and had to bleed several times(went through over a quart of fluid, but it needed a flush anyway), and I still don't think I got it all. If you're sure the system is bled, then a new MC should fix the problem. But you'll have to bleed the whole system again. Here's a couple threads of mine - just went through the whole ordeal:
http://forums.corvetteforum.com/show....php?t=1064329
http://forums.corvetteforum.com/show....php?t=1066267
Here's a good page on brake troubleshooting with a good section on booster testing down the page:
http://www.classicperform.com/TechBo...oubleshoot.htm
Are you sure you got all the air out? I just replaced my MC and had to bleed several times(went through over a quart of fluid, but it needed a flush anyway), and I still don't think I got it all. If you're sure the system is bled, then a new MC should fix the problem. But you'll have to bleed the whole system again. Here's a couple threads of mine - just went through the whole ordeal:
http://forums.corvetteforum.com/show....php?t=1064329
http://forums.corvetteforum.com/show....php?t=1066267
Here's a good page on brake troubleshooting with a good section on booster testing down the page:
http://www.classicperform.com/TechBo...oubleshoot.htm
Last edited by Ric80; Apr 20, 2005 at 12:06 AM.
Race Director
Joined: Mar 2001
Posts: 11,601
Likes: 0
From: San Francisco CA
St. Jude Donor '07
I had the spongy pedal syndrome and replaced everything. Well, everything except for the booster. The problem still remained, even though I had all new components. Swapped out the booster and it locks up all four. I know they don't go out very often and I don't know what was wrong with mine, but it did go bad. It was like it wasn't pushing on the mc hard enough, despite bottoming out the pedal. Unfortunately, I don't think there's any way to test it without swapping it. Something to keep in mind while you tear things apart. Good luck!
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
if the bolts are on the firewall/interior side then i should have a problem since my whole interior is out....... i figure for the extra 60-70 bucks i mine as well get the new booster...the car has been sitting for most of it's life since 77 so mine as well change it since everything else on the car is new or rebuilt..
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Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
Originally Posted by Ric80
Someone will correct me if I'm wrong, but if the booster is bad, I don't think you would have a spongy pedal, you would have a rock hard pedal. And from what I hear, the booster is a real pain to change. The nuts are up under the dash, on the other side of the firewall behind the booster.
A bad booster will typically not assist. The brakes feel somewhat like they do without the car running. The pedal travel is about the same but it takes a lot more foot pressure to stop the car. Some symptoms of a bad MC are the brake pedal goes to the floor all at once, brake pedal slow creeps to the floor while the brakes are applied.
I don't think you want to change the booster unless you have to. The easiest part is opening up your wallet for a replacement. A couple of nuts are real tough to get at and getting the little clip that locks the pin onto the pedal is also a chore.
Last edited by mandm1200; Apr 20, 2005 at 09:39 AM.
