Stuck brake caliper piston...

GBsPanhead

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So, all the parts starting to come in for the disc conversion. I got word today that the left caliper I ordered wont be shipping. Didn't exist from seller. Anyway….

Both the old OEM calipers have pistons I can't fully remove. Pistons come out maybe about a 1/2 inch. Can push pistons back in, use compressed air...and piston comes out about 1/2"

Thinking about rigging up a grease gun and brake fitting, and try that. Or maybe hook the caliper up to my current brake system, and use that to try and push piston out. Don't really want to try that, in case something goes haywire. Then my car wouldn't be drivable.

I'm watching youtube videos, some good ideas like a handheld hydraulic pump....costly though. Still researching that one.

Any ideas how to get these stuck pistons out of calipers? Thanks!
 
I've always used (and had success) with compressed air and if need be a shot of PB Blaster or another penetrating oil to lube things up. I always place a rag in the caliper to prevent piston damage. Wear eye protection, good gloves and keep your fingers clear.
 
I've always used (and had success) with compressed air and if need be a shot of PB Blaster or another penetrating oil to lube things up. I always place a rag in the caliper to prevent piston damage. Wear eye protection, good gloves and keep your fingers clear.

I had these soaking overnight in WD40. Probably try another like PBB. That's what I been using to move piston is the compressed air.

When all goes to plan....that piston comes flyin' outta there!!
 
The grease gun idea will work if you can get a zerk mounted, when using compressed air to force out a piston put a 2x4 in the caliper to soften the blow when it comes out.
 
At the mopar shop we had an old standard brake MC mounted on a frame with a pedal. Brake hose hooked it up. Worked well for single piston calipers. For the dual ones, one always comes out first, so we put in the new seals in that one and put it back together with a c-clamp to hold it in place while the other one was forced out. Field method.

Dave
 
Be sure to clean all of the WD 40 and PBB off as that stuff does not play well with brake fluid.

Dave
 
Got it! OMG! Ballpeen hammer, punch and pipe wrench. Tap, tap, tap, turn piston a bit with pipe wrench....tap, tap, tap Over and over! I'm OK with that because original plan was to rebuild these with new seals and piston. Bores look good, no pitting. Pitting and bubbling was actually on the pistons, not the bore.

Now I can order some new seals and pistons. Going to research on honing the bore if necessary and what all that entails.

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They do make a three stone hone for that purpose, similar to a brake cylinder hone, but bigger. Caliper bores are pretty good metal and they usually do not pit. Be sure to Mic the bores to be sure that they are still round.

Dave
 
A local rebuilder such as Fleetpride might be a good choice to go thru those. It’s not that expensive considering how hard to come by some calipers are nowadays and with the added bonus of 99.9999% successful operation when returned. They are also a great source for new from scratch driveshafts. I’ve had great luck with these guys and they are a multi state outfit that’s been in the industry for years & years.
Good luck & looking good.
 
I've always used (and had success) with compressed air and if need be a shot of PB Blaster or another penetrating oil to lube things up. I always place a rag in the caliper to prevent piston damage. Wear eye protection, good gloves and keep your fingers clear.

Seems like a perfect opportunity to put that raccoon/possum trap that everybody has laying around to good use.
Maybe even throw it in a 5 gallon bucket and just stay clear of the top as you work would be a good safety solution.
 
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