SEIZED PISTONS OUT OF CALIPERS - Help Please

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gordon
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SEIZED PISTONS OUT OF CALIPERS - Help Please

Post by gordon »

Can you help with any ideas please.?

I have callipers off of my MK 1 Pre-Facelift. They were seized but I have managed to get one piston out of each caliper by using a foot pump and blowing air through the brake pipe entry. The other one in each caliper is still well seized. They two that I have out appear to have been slightly rusted in the top of the pots.

I have tried puting my finger over the hole in the empty piston chamber and compressing air, but this is near impossible. I have cleaned up the piston that is out and put it back in the chamber, used a metal bar through the caliper middle with a spacer and again compressed air through my foot pump at up to 80 Psi. The piston all cleaned up works fine but the other one won't budge.

I have now soaked the stuck pistons in WD 40 and left them.

Does anyone have any other ideas I could try?

Many thanks - Gordon

Many thanks

Gordon



demo2
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Post by demo2 »

Is the braking system still all on the car? if so i did this once:
I put the cleaned up piston back in and pushed it all the way home, pop it on the disk with no pads and put a piece of flat bar between the disk and the piston and then bleed the system and push the piston out using the hydraulic pressure.

Capri2.8i
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Post by Capri2.8i »

Hi m8, Dont use wd40, it swells the rubber seals. I'm afraid you will need to work hard at getting it out unless you can couple it up hydraulically. Get the caliper in a good vice and try turning the piston back and forth using brake fluid as lubricant. I use large "mole grips" and if you are lucky you will get a small amount of movement. Once you get some movement, try the air again, I use my compressor. It will mean putting the other piston back in and packing it out with a bar etc to stop that one coming out. The stuck one will come out, but you will need patience.
Gluck.. John

bortaf
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Post by bortaf »

I usually soak the whole caliper in a bucket of diesel for a week or so, it will destroy the seals but if they are as bad as you say they are gonna need changing anyway so try some WD40 see if it frees them and just replace the seals after.

roopamapco
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Re : SEIZED PISTONS OUT OF CALIPERS

Post by roopamapco »

Some of you might think of a vintage motorcycle as having only drum brakes. On the contrary, since the disc brake hit the market in the early 1970?s, it has been a great performance upgrade to the older drum style brakes. Disc brakes are great until the bike sits for a long time, when the metal housings start to rust and the fluid turns into a jelly-like goo. Then the front brake pistons no longer move in and out or in the worst case, the brakes are frozen solid to the brake disc. Now you are faced with repairing the brakes, replacing the seals and perhaps the rusted pistons.
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Roopa

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