Is this caliper toast?
 

Was trying to rebuild this caliper yesterday. Couldn't figure out why the piston wouldn't extend until we took off the boot and found this. We usually use a bike pump to blow out the piston but that method didn't work this time. Should I use a compressor or is the piston and caliper rusted beyond hope?
http://forums.pelicanparts.com/uploa...1150819398.jpg
http://forums.pelicanparts.com/uploa...1150819439.jpg
http://forums.pelicanparts.com/uploa...1150819473.jpg

Does look like crap. I'd get it out wit air compressor, inspect the bores and try a mild sanding. Hopefully the piston isn't pitted out.

Amazing what salt air does to a car.

rjp

May be wrong, but it looks like an A caliper to me. You should be able to find a decent one for cheap. Buying another one would make up the time you'd spend trying to make that one good, & this one might not turn out like you want it. Do the inside passages have a lot of rust also?

Thanks Randy. I'll try the compressor next.

Yes Marv, the inside passages have rust as well. I'll ask around for a good, used, LH front A caliper if I can't blow out the piston and clean it up. New ones from Pelican are just a little under $300!

Should calipers be replaced in pairs?

My opinion is to replace it with a new caliper (and the opposing caliper). That looks very painful, and in the end you probably will not be happy with the end result.
If your heart is set on rebuilding this one, I'd soak it in PB Blaster and let it sit half the day and then try expanding the cylinder.
Good Luck and have fun with it!

Can I recommend cleaning or bead blasting it before you try and get the piston out? You want to minimize contamination of the bore and fluid passages.

Hey guys... using an air compressor can lead to the loss of fingers!

Rig up an adapter and pump the puppy full of grease. Yes I know its messy but it pushes out the pistons SLOWLY and lots safer.

Then you can sit the caliper in some solvent and take a good look at it. To clean up the rust put it in a sand or beadblast cabinet. Looks like surface rust to me but you need to see how the bores look to tell.

Joe A

Agree with Joe, I'd be VERY careful getting that out with compressed air. I can guarantee it will sound like a cannon when it finally pops. Try not to be near it..

I just did mine 2 days ago with an air compressor. I started with a small wooden handle and then used cardboard when popping the pistions out. Once the inner piston is almost out use the C-clamp method on the inner piston to hold it in place. Proceed to take the outer piston out. Once I got the outer piston out I plugged the hole with cardboard, held it tightly when using the air and it popped the inner piston out.

Use a piece of 2x4 between the pistons. Using an air compressor isn't bad at all. When the 1st one pops loose, put it back in the bore, and wedge the 2x4 against it with a C clamp to hold it in place then break the 2nd piston loose.

Whatever you do, don't attempt to put your hand to catch it. It'll break fingers.

That thing is screaming for a good soak in cleaner and glass beading.

rjp

The easiest way of all to remove them is with them still on the car, with a helper operating the brake pedal. You can slowly push them out with hydraulic pressure. Use the same caution as with compressed air though. Propping wood in there is a good idea so they don't go flying.

Chris are those yours?

You can ask Doug about rebuilt calipers, I think he spent about $85 each?

Drawing on old memories though, best to call him and ask him where he got them.

I'll shoot you an email right now with his email addresses....

-Chris

For what it's worth, Kragen lists rebuilt calipers on their web site. As low as $51 for the front, and $43 for the rear, with a core charge.

If you want to be the gunea pig, print out the page and take it in with you. The register monkeys will try and charge you full price, up to twice as much as the internet price.

Tom

Question is, is this for rebuilt Porsche calipers, or rebuilt calipers in general; starting as low as $51?

I dont recommend blasting or glass beading in or around the pistons, as you will want to only lightly polish or fine sand them. (Only a couple of tenths of a thousandth) to clean them up.

Point taken on the 51 bucks. I'll bet they don't use ATE kits. Maybe they do.

On the blasting, I think he said to do it before removeing anything, thereby not getting any of the medium in the bores. Sounds reasonable.

On the grease, it takes a fair amount of grease and even more solvent, then alcohol to get the things clean. I know it's safer, but.........

That is what they list for a 911 SC. There are a couple different choices of what appear to be commercial rebuilds, Cardone, Raybestos, Beck-Arnley, Bendix and Crown. Unfortunately, some of them only seem to come "loaded" with street pads.

Tom

SCs had "A" calipers. For $51 I'd try them. The calipers are simple. Plus upgrading pads isn't expensive. You don't have to replace both calipers as long as the other one is working well. Like I said, forget that one. You're going to have to buy a kit, try to clean up the outside of that caliper, clean out the bore (which is hard to reach into), see if you can clean out the passages if they are really cruddy (& then you'll never be able to do a good job), and you're going to have to guy new pistons anyway. For me, it's a no-brainer. But, sometimes it's fun to resurrect something, if you have the time.