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Discussion Starter #1
Looking for a set of working or rebuildeble (as in not completely frozen) rear calipers. 1971 GTV.

I tried every trick in the book to unfreeze mine eventually breaking a piston. I give up.

As always,

Thanks!
 

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Sent you a PM on the calipers. Also this:

The trick to unsticking the pistons is to hook the caliper back up to the axle and pop them out with hyd. pressure. The rotor should be in place as well. You'll need to replace the brake pads with a 1/8" metal shim (the backing plate to a worn down brake pad works great) so that the first piston to pop out doesn't pop all the way out. That way you still have hyd. press. for the 2nd one to pop out. I've never had any luck with unsticking a piston with air pressure. Hope this helps!
 

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Sent you a PM on the calipers. Also this:

The trick to unsticking the pistons is to hook the caliper back up to the axle and pop them out with hyd. pressure. The rotor should be in place as well. You'll need to replace the brake pads with a 1/8" metal shim (the backing plate to a worn down brake pad works great) so that the first piston to pop out doesn't pop all the way out. That way you still have hyd. press. for the 2nd one to pop out. I've never had any luck with unsticking a piston with air pressure. Hope this helps!
I have done it with compressed air or nitrogen from a high pressure cylinder but it is dangerous due to the stored energy release when the piston does break free at some times over 1000 PSIG. I used a piece of plywood to block/limit the movement of the releasing piston.

Bills method is likely to work and is much safer. If the master cylinder will not make enough pressure then another source of hydraulic pressure should be used.

FWIW

Ken
 

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sometimes they just won't come out, no matter what you try. I gave up too after trying all the methods suggested on this great board :eek:
 

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Discussion Starter #5
I tried soaking the calipers in penetrating oil for a few days, heat, and air pressure and finally reattached to apply hydraulic pressure. Nothing could break them loose. I even fabricated a fitting so that air pressure was threaded directly to the caliper with no leaks.

I eventually broke a piston banging on it. After that I just wanted to see if I could get the darn thing out so I split the casing and filed a slot in the piston and tried to get it to turn with a hammer and chisel. Wouldn't budge! I think 10 years in a damp Midwest barn took its toll...

The front calipers were much easier to pursued…

Anyway – Thanks to Bill S I’ll have a set soon.
 
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