Vacuum booster
Thread Starter
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Vacuum booster
So I removed the Hydroboost and put a brand new GM AC Delco vacuum booster on the car. I bought it from Eckler since they were having a sale a while back. Now I am finally running the LS motor and getting things dialed in. The brake booster I feel is crap. When. I depress the pedal it moves about an inch with a clunk and then I hear a vacuum leak while the pedal is depressed .When I let go it does not come back fully up. I fear this unit is crap. I usually don’t deal with Ecklers because their returns are usually denied. I will try but now looking for a good aftermarket unit. Not looking for bargain basement but also don’t want to drop a ton on this. What are you guys running. The car has Wilwoods on all 4 corners with a WIlwood MC.
Le Mans Master
Joined: Apr 2001
Posts: 5,941
Likes: 281
From: Was New Orleans but swam to Baton Rouge LA
Cruise-In IX Veteran
Mine is still in the box, but I got it from Corvette SS brakes. They also make a nice tool to make sure your booster to master cylinder rod is adjusted properly. Here are the links:
Booster
http://www.cssbinc.com/1968-76corvet...ter338906.aspx
Tool
http://www.cssbinc.com/1968-76corvet...tmenttool.aspx
Booster
http://www.cssbinc.com/1968-76corvet...ter338906.aspx
Tool
http://www.cssbinc.com/1968-76corvet...tmenttool.aspx
Drifting
Joined: Dec 2011
Posts: 1,742
Likes: 289
From: Chardon Ohio
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
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From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Btw, why are you replacing the hydroboost?
Last edited by resdoggie; May 3, 2019 at 04:56 PM.
Thread Starter
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Didn't like it. It was not a linear feel when braking. I actually like the manual brakes on my Cobra the best of all. Takes a slight bit more effort but you always know where you are in braking. Just my opinion. Its not for everyone.
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Thread Starter
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Yes I did. Actually not much movement once I can feel it "engage". The brake part of it works fine. I have plenty of good pedal. It is something in the booster. I hear it hissing at me when the brakes are applied. When I release it the hiss goes away.
Drifting
Joined: Jun 2015
Posts: 1,340
Likes: 753
From: Doctors Inlet Florida
I actually love the non-power brakes on my Corvette. Just a new Delco master cylinder, Vette Brakes o-ring calipers and whatever pads they shipped with them. The pedal has a great feel and the car has smooth confident stops.
Last edited by Crimson Thunder; May 5, 2019 at 03:19 PM.
Thread Starter
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Just a quick update. I went ahead and bought another booster. This one was from Tuff Stuff. Took it out of the box and right aways started to move the shaft in and out. Feels much better. I hooked up my vacuum pump. Sucked out the air and it held 5 in of vacuum for 5 minutes. Tested the brand new AC Delco from Ecklers and it dropped 2 inches of vacuum the first 2 minutes. Obviously something wrong with this unit. Removed it and installed the Tuff Stuff one after checking all the clearances and adjustments. No more clunking when the pedal is depressed and all seems much better. Still waiting on a part for the motor to fire it up and check it under full vacuum. So it seems like the 3rd time is a good booster. 1 rebuilt unit that looks like crap, 1 brand new AC Delco worked like crap and finally the Tuff Stuff one looks to be the ticket.
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
Just a quick update. I went ahead and bought another booster. This one was from Tuff Stuff. Took it out of the box and right aways started to move the shaft in and out. Feels much better. I hooked up my vacuum pump. Sucked out the air and it held 5 in of vacuum for 5 minutes. Tested the brand new AC Delco from Ecklers and it dropped 2 inches of vacuum the first 2 minutes. Obviously something wrong with this unit. Removed it and installed the Tuff Stuff one after checking all the clearances and adjustments. No more clunking when the pedal is depressed and all seems much better. Still waiting on a part for the motor to fire it up and check it under full vacuum. So it seems like the 3rd time is a good booster. 1 rebuilt unit that looks like crap, 1 brand new AC Delco worked like crap and finally the Tuff Stuff one looks to be the ticket.
You must be EXTREMELY well versed with getting to those four booster attachment nuts.
I feel for you.
Glad you are on the right path now.
Craig
Melting Slicks
Joined: Nov 2003
Posts: 2,668
Likes: 118
From: St. Charles Mo
CI 5 & 8 Veteran
Gordo, I to went with the Wilwood brakes and master cylinder on my Blue Dart 541 69. I added a vacuum pump to supplement the low engine vacuum on that engine. (9-10 in/HG) I plumbed the lines so the engine or'd with the pump got the original stock booster and the surge tank to ~ 20 in/Hg before pump shuts down. The vacuum switch will turn it back on around 16inHg. Holds vacuum for a long time or until I step on brakes and pump has to catch system back up. This does not happen immediately as you can imagine. Brakes work fine at >15 in Hg, but lousy below that (i.e. 9-10 inHg) Stepping on brakes saps vacuum back to engine levels. Is this normal for these old boosters? The engines with high vacuum have a much faster recovery I'm sure. Plan to call Wilwood and ask about dual diaphragm options wondering if that would be more vacuum efficient???
Anyone with knowledge in this area?
P.S. I put the rest of the vacuum system behind a switch which I can control from cockpit. Trying to keep the headlights, wiper door, A/C system from contributing slow leaks is a mountain to tall. LOL
Anyone with knowledge in this area?
P.S. I put the rest of the vacuum system behind a switch which I can control from cockpit. Trying to keep the headlights, wiper door, A/C system from contributing slow leaks is a mountain to tall. LOL
Last edited by Bullshark; May 11, 2019 at 06:28 PM.