Spongy brakes

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Spongy brakes

Postby thrnelson » Sun Jul 28, 2019 10:19 am

Help! On July 4 my wife and I took the comet on a four hour drive and it did great until the last half hour when the brakes got spongy. It acted like the master cylinder was bad so I replaced the master cylinder and the brakes are still spongy. They won't even pump up. I have checked for leaks and bled the brakes. I took the comet to a local brake shop and they could not figure it out. Any ideas you have would be appreciated.

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Re: Spongy brakes

Postby poboyjo65 » Sun Jul 28, 2019 1:20 pm

Maybe the new one still has air? did you bench bleed it? mine are a little spongy but I use dot 5 & it is a little spongy feeling. but sounds like you have a definite change. if drums on rear; have you pulled them to look at wheel cylinders?
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Re: Spongy brakes

Postby thrnelson » Sun Jul 28, 2019 5:05 pm

Yep. I bench bled the master cylinder. When I say the brakes are spongy I mean dangerously so to the point where it is not safe to drive. I use dot 3 fluid. I'm not losing fluid and I even took it to a brake shop to have them check my work. I have tried five different shops in my area and I end up doing the work myself. It is very challenging to find somebody to help.
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Re: Spongy brakes

Postby tomb22 » Sun Jul 28, 2019 8:21 pm

I would check all the rubber hoses to make sure non of them are ballooning. If not then replace the master again. Just some suggestions.
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Re: Spongy brakes

Postby Jims65cyclone » Sun Jul 28, 2019 9:09 pm

What master cylinder do you have? Fruit jar or dual chamber? Manual or booster? Does the pedal go to, or almost to the floor before firming up? Any dampness/darkness on backing plates?

Jim
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Re: Spongy brakes

Postby lavron » Sun Jul 28, 2019 11:59 pm

tomb22 wrote:I would check all the rubber hoses to make sure non of them are ballooning. If not then replace the master again. Just some suggestions.
tom


I think I am with Tom on the rubber hoses.

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64 Comet 202 Sedan, My first car, I have owned it since 1979!
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Re: Spongy brakes

Postby Red65Cyclone » Mon Jul 29, 2019 7:41 am

Mine did the sane thing. I'm using Dot 5 and couldn't get the sponge out. Turned out the shoes were to far off the drums. I manually adjusted all four corners and presto, I had brakes. No guarantee, and your results may differ.
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Re: Spongy brakes

Postby thrnelson » Thu Aug 01, 2019 7:09 am

Thanks for the ideas. I will check the hoses when I get back home. I'm traveling right now. I will let you know how it turns out.
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Re: Spongy brakes

Postby thrnelson » Thu Sep 26, 2019 7:49 pm

It's been a while since I had time to work on comet, two months to be more precise, I found the problem with my brakes. It ends up my left rear drum brake hardware exploded and fell apart. Put everything back together and adjusted the adjuster and the brakes work better than ever. I only wish I could have gotten to it quicker. I hope this helps somebody else in the future.
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