Stuck caliper pistons

cosmo · 10-07-2002, 08:10 AM

I'am trying to rebuild the front and rear calipers on my 71 E. This car has been sitting undriven for 20 years. All of the pistons are stuck and I don't have any idea how to get them out. I have split the calipers and soked them in penetrant for 2days and they are still stuck. Any ideas

Cosmo
71E

Superman · 10-07-2002, 08:16 AM

Normally, you leave the calipers together and use compressed air to blow the pistons out. With a rubber-tipped air nozzle. And a block of wood, since the piston is going to come out with some scary force.

cosmo · 10-07-2002, 08:18 AM

Compressed air, at least 150 psi won't budge them.

Jdub · 10-07-2002, 08:57 AM

Get them to a professional. There is no need to hurt yourself with these calipers: they may only be good as core now.

Or the pucks have gone cockeyed or are rusted in. No matter, you are probably best with smooth-moving new calipers at this point.

Point of reference: I removed the pucks in my SC calipers with a bicycle pump.

John

dtw · 10-07-2002, 09:23 AM

Are the fronts aluminum "S" calipers? These would be OE for a 71E. If you are having that much trouble with them, I would expect that the bores are trashed. If the car was sitting that long, I would expect that corrosion has caused some "swelling" in there causing your problems. Replacements are still plenty easy to come by, there is a set from a seller I trust on eBay right now:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1866464849

If they are the standard iron calipers up front, no worries. Sets of those are really really easy to come by. If you need fronts and/or rears, let me know. I've got several sets of each. I can supply you with cores ready to restore, or I can set you up with ready-to-install.

Note- it is generally inadvisable to split these calipers. It is very difficult to get a good seal afterwards.

Superman · 10-07-2002, 09:23 AM

I'd agree. 150 psi is beyond reason. My caliper pistons, under 150 psi, would be handling about 500 lbs of pressure, total. Too much. Too dangerous. Perhaps take them to a pro. Or maybe wait and see if Warren or JW has a suggestion.

dtw · 10-07-2002, 09:26 AM

Quote:

Originally posted by Jdub
Point of reference: I removed the pucks in my SC calipers with a bicycle pump.

Another reference point: I removed pistons from S-calipers which had been sitting for 10 years (including being submerged at least once in a hurricane) with 90 lbs of air- they popped right out. At 150 lbs I would not have the stones to try this.

lcjjbeav · 10-07-2002, 11:32 AM

Had same prob. on my '70e. Was able to move piston back in slightly with c-clamp but 100psi air still didn't budge them out. Reparied MC then hooked rears up to front brake line (shorter run) and was able to pump them out easily. Hyd pressure always better than air (won't compress). Read here before someone uses a porta-power with adapter fittings. Where in TX? Sounds like we are on a similiar quest (waking the sleeeping Pcar).

john walker's workshop · 10-07-2002, 11:54 AM

i always pop them out with the brake pedal. pull out one pad at a time, pump out the piston, clean up the bore and piston, put in a new o ring, and squeeze the piston back in. then do the other piston the same way.

Joeaksa · 02-12-2003, 12:57 PM

Rebuilding my brake calipers and looking for info and tips.

Found this thread. If anyone has problems getting their brake pistons out of the housing, go to a parts store and get a grease nipple that will fit onto a grease gun and also screw into the caliper bleed hole.

Slowly pump grease into the caliper and if one piston comes out faster than the other use a "C" clamp to adjust this. The grease WILL push the piston out and slowly and much safer than using shop air.

Joe