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I put a Wilwood front disc conversion kit on a 67' Camaro. Still have original discs on rears. I have added power brakes with new Classic Industries booster, master cylinder and proportioning valve. Here's what's on it this far:

- Porportioning Valve Set from Classic Industry; 391350; http://www.classicindustries.com/controller.cfm?type=product&action=getProductsCategorySearch&productSearchCatalogId=1&categoryId=98&subCategoryId=796&yearId=0&partNumber=391350&keyword=

- Power Brake Booster; Classic Industries; D800300; http://www.classicindustries.com/controller.cfm?type=product&action=getProductsCategorySearch&productSearchCatalogId=1&categoryId=98&subCategoryId=794&yearId=0&partNumber=D80030&keyword=

- Master Cylinder; Classic Industries; E358; http://www.classicindustries.com/controller.cfm?type=product&action=getProductsCategorySearch&productSearchCatalogId=1&categoryId=98&subCategoryId=789&yearId=0&partNumber=E358&keyword=

Here's the problem:
After the car warms up (2 or three miles), the brake peddle starts to become 'hard' and the front brakes start to come on. The left front brake consistently has more pressure on it than the right, but both have pressure locked in the cylinder. I've adjusted the shaft that runs from the brake peddle, through the fire wall in to the power booster. I was told that maybe the shaft was too close to the power booster and causing pressure to build. Anyway, I've backed the shaft off by 5 to 6 full turns, probably 1/4" to 3/8" and am sure it's not putting pressure on the booster.

I've also been told that in my setup I should have no porportioning valve for the front brakes and (I think) a 10 PSI valve for the backs. Per Classic Industries I have the right valve.

Any ideas...calipers? Everything is new..new stainless lines, new Wilwood kit, new, new, new...so I'm a little baffled.
 

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the culprit looks like the proportioning valve that's the for a drum/disc set up, it easy to see because there's a rubber cover on the front and that's for the relief valve a disc/disc valve will not have one, its a common problem, you must switch this Combi-valve to insure proper brake Bias(front to rear braking balance)

classic industries (incorrect picture)
disc/disc valve

steves camaros
disc/disc valve
 

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While I agree the prop valve looks wrong, that should only affect bias front to rear, and have nothing to do with releasing the brakes. I think you have a constant pressure problem pushing on the brakes all the time ever so slightly which gets worse as the pads get hotter and hotter and grab more and more. Sounds like the push rod in the booster is too long and is pushing on the piston in the master. Take the master loose and see if you push it tight to the booster by hand if it trys to spring back away from the booster right at the bottom. If so the rod in the booster is too long and your never completely releaseing your brake. As i said, cold, you can drive through it. but the pads are designed to get mnore aggresive as they get hotter. Hence why it gets worse longer you drive it.

A quick test is remove the master (do not have to remove the lines) and put a thick washer (lock washer is perfect) between the master and booster. And try that. If that makes it better, you will have to grind the rod coming out of the booster down to fit.
 

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:thumbsup: good call frank
Well, lets see what the OP says after the test before awarding me the win!, LOL! Problems like this are a PIA to say the least. Not knowing the supplier (to Classic) of the parts, quality, could be in the master. The best products have the possibility of a faulty one occasionally, but some cheapo stuff has a much higher level of failure. Not saying this is or isn't. I know we tried some of the cheapo stuff, was more trouble then it was worth.
 
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