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Whats causes a caliper to go bad?

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Old 03-28-2009, 06:51 PM
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Default Whats causes a caliper to go bad?

I just did a brake job on my car last week (front pads and rotors) the left side is fine but the right caliper bottom piston is stuck. where i compressed the pistons i put an old brake pad on the two pistons and used one c clamp to compress em in all the way and evenly. i put it all back together and only one of the pistons is working now. i already bought a new caliper and am about to replace it but i dont understand why it would go bad after i do a brake job because it was clearly working before i did the brakes.
Old 03-28-2009, 09:08 PM
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I know you said you pressed it down evenly but it just sounds like one piston is jammed in there crooked so it can't move.
Old 03-28-2009, 09:15 PM
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I'm thinking if you put a deep socket or a pipe inside the piston so it fits somewhat snuggly and move it around you might be able to get it to break free. You have the dust seals on the outside so you don't want to mess those up by wrenching on the outside of the piston. Be sure to check for leaks if you get that caliper working and decide to stay with it...
Old 03-28-2009, 09:51 PM
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same thing happened to me. usually there is rust or something in the back of the bore, and the piston is out farther than the rust. once you press the piston back in to reset them, now it is in the rust and stuck. you may be able to work it out, but its probably not worth it if you already have a new one.
Old 03-30-2009, 10:19 AM
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I had a piston seize in one of my calipers too, my drivers side. I kept working with it and tapped the backside of the caliper with a rubber mallet till it cam loose. After that the car braked funny for awhile. If I was 100+ I could feel the brakes pull under heavy braking to my drivers side. I decided to tear my brakes apart one day to see what the problem was. I must have heated my brakes way too hot because i melted the dusted boot and expanded the seal. I went to my dealership and ordered new seals for the entire front. was around $40. Car brakes great since.

Note that our pistons are made of steel, which is a great reliable metal, but once heated well enough.. it stays hot longer than an aluminum or stainless piston would. Although aluminum has a quicker heating and cooling rate and a higher overall temperature, steel stays hot longer causing more damage. Plus steel rusts and can cause debris to interfere with your pads.

You should get some high heat paint.. krylon makes stuff for grilles for like 4 or 5 bucks, gently mask around your rubber boots and paint that inside part of your pistons to prevent rust from getting in there. This will make your piston's life last longer during brake changes.

Another thing about brakes is balance. I was always taught that if your doing one side of the brakes... always do the other. Never replace just one brake hose or caliper or pad at a time. It will cause an uneven braking behavior. Brake lines and calipers can get build up in them over time restricting flow. By replacing only one side fluid will travel quicker since there is less restriction. Thus pushing that caliper's piston forward before the other. You may never feel much of a difference but when your flying down the road and need to stop fast, you might get a feel of what I'm talking about.

Id replace both calipers to be safe or just buy new perfomance ones to really take advantage of our weak stock design. Make sure to use the pad sealer to the pistons so built up gas does not get behind your pistons and heat them more causing more damage.

Good Luck
Old 03-31-2009, 08:33 PM
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hey guys I have a questions along these lines. I just took my calipers off and apart today and started cleaning them. The one was just fine cleaned up pretty good already for just the first session.

The second one however, I've dissambled the caliper and I noticed that one of the piston seals is damaged and torn. I'm sure its obvious I should replace it but I don't know how I haven't really tried to rip the piston out of the caliper, is that possible? How do you take the seal apart and replace it?
Old 03-31-2009, 09:41 PM
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Originally Posted by Bouvs
hey guys I have a questions along these lines. I just took my calipers off and apart today and started cleaning them. The one was just fine cleaned up pretty good already for just the first session.

The second one however, I've dissambled the caliper and I noticed that one of the piston seals is damaged and torn. I'm sure its obvious I should replace it but I don't know how I haven't really tried to rip the piston out of the caliper, is that possible? How do you take the seal apart and replace it?
I've used this before to rebuild one caliper that was leaking: http://www.installuniversity.com/ins...er_rebuild.htm

Alot of people will just say to replace the whole caliper which is fine but if you already have the caliper sitting on your workbench cleaning it then it is easy enough to replace the seals. The dust boots can go fit in there backwards so just do one at a time and use the other caliper as a model.

Last edited by wht01ws6ta; 03-31-2009 at 09:53 PM.
Old 03-31-2009, 09:42 PM
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Originally Posted by Bouvs
hey guys I have a questions along these lines. I just took my calipers off and apart today and started cleaning them. The one was just fine cleaned up pretty good already for just the first session.

The second one however, I've dissambled the caliper and I noticed that one of the piston seals is damaged and torn. I'm sure its obvious I should replace it but I don't know how I haven't really tried to rip the piston out of the caliper, is that possible? How do you take the seal apart and replace it?
my drivers side was the same way. you can get the boot off its just a pain in the a$$. call ur local chevy dealership and they can get you one for like ten bucks. if i can remember it is called a caliper piston dust boot. all it really does it keep it from rusting inside the piston and also helps keep gases from entering the caliper and causing it to overheat. i ran it with the boot cracked for a lil while before i replaced. it aint vey major but if you dont want to replace that caliper (and cause braking toubles) i would suggest replacing the boot as soon as you can. on another note if you are leaking fluid it aint worth your time to reseal it cuz it only cost around forty dollars at advance auto parts, autozone, or o reillys auto parts. so good luck buddy!!



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