1973 Corvette Rear Brake Problems
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Intermediate
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1973 Corvette Rear Brake Problems
I have recently moved on to working to fix the brakes on my 73'. The front brakes work perfectly but no matter what I do I cannot get the rear brakes to work properly. I have replaced both back calipers, pads, rubber lines, metal lines, and the Master Cylinder but they just won't work right. At first, when I replaced these parts and bled the brakes I had solid brake pressure in the back, Then after about a half hour of driving, I would lose rear brake pressure. I would then bleed them again and the same thing would happen. I then realized that one of the calipers was leaking so I assumed it was a bad caliper. After exchanging the caliper, the same thing happened and that caliper began leaking too. Then the caliper on the opposite side also began to leak. I have no idea what would cause this and why all of the new calipers on the rear have started leaking while the front brakes remain fine. Any Ideas?
1967 Pedal Car Champion
Joined: Mar 2020
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From: US-PNW
I'm curious how you know the rears have "lost pressure". The dash warning light? Pedal feel softens?
As others above questioned, where are the calipers sourced? And, where are the leaks appearing?
As others above questioned, where are the calipers sourced? And, where are the leaks appearing?
Thread Starter
Intermediate
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The dash warning light turns on, and the first 1/4 of the pedal goes away. The leaks seem to come from one of the pistons. And the calipers came from autozone.
1967 Pedal Car Champion
Joined: Mar 2020
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From: US-PNW
I may have missed it in AutoZone's description, but it doesn't appear these are stainless lined bores. If not, then being remanufactured, they are either left pitted or cut oversize to clean up the walls. Both scenarios risk leaking because the seals are not as effective as they should be. You want to ensure you're getting stainless lined calipers. Rock Auto lists both Delco and Raybestos branded with stainless sleeves. Package kits from the regular Corvette vendors are more than likely from Lone Star and are a decent value.
Melting Slicks
Joined: Feb 2007
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From: S.E. MI
St. Jude Donor '15
Autozone calipers are rebuilt in Mexico now. They sandblast and paint the bores. Every single one of them will leak.
Take them back and get ones from Muskegon Brake or one of the other suppliers who sells American built ones like Lonestar
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Just buy the kits and do it yourself in that case. Or get stainless sleeved original Delco Moraine castings rebuilt from Lonestar if your cores aren't rebuildable.
Melting Slicks
Joined: Feb 2007
Posts: 2,709
Likes: 269
From: S.E. MI
St. Jude Donor '15
Thread Starter
Intermediate
Joined: Mar 2022
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I believe the first portion of pedal travel is acting primarily on the front brakes and only after increased pedal pressure do the back brakes begin to be applied (so as not to lock up the fronts).
I may have missed it in AutoZone's description, but it doesn't appear these are stainless lined bores. If not, then being remanufactured, they are either left pitted or cut oversize to clean up the walls. Both scenarios risk leaking because the seals are not as effective as they should be. You want to ensure you're getting stainless lined calipers. Rock Auto lists both Delco and Raybestos branded with stainless sleeves. Package kits from the regular Corvette vendors are more than likely from Lone Star and are a decent value.
I may have missed it in AutoZone's description, but it doesn't appear these are stainless lined bores. If not, then being remanufactured, they are either left pitted or cut oversize to clean up the walls. Both scenarios risk leaking because the seals are not as effective as they should be. You want to ensure you're getting stainless lined calipers. Rock Auto lists both Delco and Raybestos branded with stainless sleeves. Package kits from the regular Corvette vendors are more than likely from Lone Star and are a decent value.