C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Brake woes, advice solicited

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Old Sep 26, 2005 | 05:53 AM
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Default Brake woes, advice solicited

I upgraded the brakes on my '86 w/ the c5 VBP package. Install went fine and the system does not leak.

I bled the system thoroughly and in the correct order(engine off). I made sure I bled enough fluid out of each line so that all the old fluid was gone.

Problem: While the car is idling, there is little to no resistance in the brake pedal unless I pump it several times. On first couple of pushes it goes straight to the floor. ... master cylinder is full, no leaks.

I have yet to road test it as I fear there is little stopping power.

What is my problem here? Solution?

Thanks all for your much needed advice.
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Old Sep 26, 2005 | 06:37 AM
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Old Sep 26, 2005 | 08:50 AM
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I would guess maybe a couple of air bubbles stuck in the new calipers, or maybe the seals are a bit worn in the MC, but isn't leaking cause the second seal is catching it. Have you tried tapping the calipers to help dislodge any trapped bubbles?
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Old Sep 26, 2005 | 10:17 AM
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Its some seal in the MC, I blew the rear seal (into the booster) about 6mos. after putting in the C5s.
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Old Sep 26, 2005 | 02:31 PM
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Ok I found a leak. It hwere the master cylinder bolts to "vacuum drum". Do I need to replace the whole unit? Buy a gasket? Solutions?


Thanks again.


Steve
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Old Sep 26, 2005 | 02:46 PM
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Rebuild or replace 1 each master cylinder. Don't let the brake fluid eat into your vacuum diaphragm otherwise you'll be replacing it too!

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Old Sep 26, 2005 | 02:56 PM
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Originally Posted by Corvette86
Rebuild or replace 1 each master cylinder. Don't let the brake fluid eat into your vacuum diaphragm otherwise you'll be replacing it too!


Damn I take it that I'll be bleeding the whole system over again?
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Old Sep 26, 2005 | 10:52 PM
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Yup. And don't forget to bench bleed your new master cylinder. I bought an original replacement m/c from ecklers for $120. Made by PBR australia, best deal by far. When ordering from Ecklers, cross your fingers.
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Old Sep 27, 2005 | 07:51 AM
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Any time your foot goes to the floor, suspect the M/C first.
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