Power brake booster

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Feb 21, 2015 | 03:38 PM

slicker358

Thread Starter

Heel & Toe

Joined: Oct 2007

Posts: 22

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Power brake booster

I have a C-4, but post this question for my neighbor. He has a 1975, 4 speed, coupe with power brakes. He worked his engine to include a more radical cam. As you might guess, now he doesn't have enough vaccuum to operate his power brakes. Did the 75 Corvette come with non-power brakes? If so, can he just get a manual master cylinder and install it in his car? He is talking about an after market brake booster that operates off the power steering pump, but it is an expensive setup. Thanks for any help.

Feb 21, 2015 | 10:54 PM

7t9l82

Le Mans Master

Joined: Oct 2010

Posts: 6,929

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From: melbourne florida

2023 C3 of the Year Finalist - Modified

see how much vacuum he has at different r.p.m's . a vacum canister from jegs or summit may well do the trick. they aren't expensive and are easy to install.

Feb 21, 2015 | 11:00 PM

'75

Le Mans Master

Joined: Dec 2007

Posts: 6,422

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From: McHenry Illinois

Either can be a good solution. The hydro-boost can be done economically. Go to the boneyard and find one from a 90's astro van, modify the push rod and have the hoses made up locally. If he switches to a manual master cylinder, the lines will have to be replaced or modified. The pushrod goes in a different hole in the pedal and I think there needs to be a different bracket for the brake light switch.

Feb 21, 2015 | 11:25 PM

Les

Race Director

Joined: Dec 1999

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From: Sierra Foothills CA

I've had the same issue with my avatar car. I decided to buy the Hydroboost kit for it because brakes are so critical to safety. If your buddy simply can't afford the Hydroboost system he'll have to crutch the problem with a canister. However, the brake guys I talked to weren't very encouraging about how much good a canister will do. Just FYI, it may not be enough to provide full clamping power. Maybe he'll get lucky.

Feb 22, 2015 | 10:14 PM

drkness01

Instructor

Joined: Jun 2014

Posts: 161

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From: Pensacola FL

+1 for hydro boost.

Feb 22, 2015 | 11:11 PM

drwet

Melting Slicks

Joined: Dec 2009

Posts: 3,229

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From: Thunder Bay

I used to have an '86 Cadillac that had an auxiliary electric vacuum pump and reservoir. Perhaps with a little research you could come up with one that could be installed to supplement the engine vacuum to run the power brakes.

Feb 23, 2015 | 06:49 PM

DUB

Race Director

Joined: Apr 2009

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From: Charlotte NC

I also agree that an extra vacuum reservoir is more than likely not going to work. It could...but I am betting it will not work WELL for the BRAKES. I have seen the electric vacuum pumps fail....they literally melt down. Just another part that is not needed.

Going manual brakes is up to your friend. SEEMS like your friend needs to treat the brake system with as much attention as he did the engine upgrades.

I would suggest using a Hydroboost.

From my experiences on Corvettes that come into my shop...what always amazes me is that some people will put a lot money into making the engine awesome...but if these modifications effect the brakes (for example)....which STOPS the car. These same people will begin to try to find a solution that does not cost them any money....and 'think' that I have a magical solution to their problem.

DUB

Feb 23, 2015 | 07:21 PM

74modified

Burning Brakes

Joined: Oct 2008

Posts: 1,037

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From: Mobile Alabama

1 more for hydroboost - if you are sure the vacuum system is all in good order. I love mine.
There are OEM electric vacuum pumps available at a reasonable cost, (diesel pickups), but they are NOT rated for brakes. They would be fine for other vacuum needs - headlights. There are probably electric vacuum pumps that are rated for brake use, but I have no knowledge of them or the cost.