# how to rebuild rear calipers??



## DUB-YAH (May 4, 2004)

anyone got a link on how to rebuild mk3 rear calipers, search didnt come up with anything usefull


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## germancarnut51 (Mar 23, 2008)

What's the problem with the rear calipers? Just need to replace the dust boots or piston seal, or do you have a parking brake problem?

There aren't any parts readily available for the internal parking brake mechanism, so if you have problems with the parking brake portion of the rear calipers, you need to replace the calipers themselves.

If you have a torn dust boot, or a leak from the caliper piston, you can buy caliper seal kits from most Online Sellers (I get mine from autohausaz.com for about $6 (does two rear calipers per kit). Again, if the leak is from the parking brake, you need to replace the caliper.

DO NOT BLOW THE PISTONS OUT OF THE CALIPERS AS YOU DO WITH FRONT CALIPERS. YOU WILL DAMAGE THE PARKING BRAKE MECHANISMS (and destroy the calipers).

You will need a caliper retraction tool set (borrow from AutoZone or other auto parts store) DON'T WASTE YOUR TIME AND MONEY ON THE TOOL NAMED "THE CUBE". I bought a caliper retraction tool set from Harbor Freight ($30 regular price, and $20 on sale) nine years ago, and it works fine for turning in the rear caliper pistons (clockwise) when changing the brake pads. BUT the rear caliper pistons need to be rotated outwards to remove them from the calipers to replace the seals, and the tool is too thick to allow the pistons to be completely rotated out (counterclockwise).

I ended up using a bicycle bottom bracket tool with pins spaced properly to engage the notches on the tops of the caliper pistons to turn the pistons the rest of the way out. There is a threads shaft that the piston engages in the middle of the chamber in the caliper cylinder. When you get the piston unscrewed all the way, you can lift it out. Remove the bleed valve, check the passage in it (replace is damaged or crushed). Clean out the gunk in the bleed valve, and the caliper with brake cleaner, check the pistons, and the cylinder walls for damage, and you are ready to reassemble (if the caliper cylinders or pistons are damaged, it's best to replace the caliper (pistons and caliper castings cost more that another used caliper).

Make sure that you allow enough time for the brake cleaner to fully evaporate before reassembly. I hose silicone spray into the caliper and on the all the parts (you can also use brake fluid, but I personally don't like having brake fluid everywhere), and I put a coat of silicone brake assembly grease on the piston, cylinder, the dust boot, and the caliper seal.

The easiest way to get the dust boot back in is to put the dust boot on the bottom of the psiton, stretch it out, and engage it fully in it's groove (upper one in the caliper cylinder), then place the piston ontop of the screw, and carefully wind/retract the piston into the cylinder, sliding the dust boot towards the top of the piston (and it's groove) as you retract the piston into the caliper using the brake caliper retraction tool. Don't force the piston in past a soft stop when winding into the caliper. Make sure that the dust boot is fully seated in it's groove in the piston before the piston is fully retracted.


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## DUB-YAH (May 4, 2004)

pistons wont turn


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## germancarnut51 (Mar 23, 2008)

What are you using to try to turn the pistons (you are trying to turn clockwise to retract, and counterclock to extend, CORRECT?)?

When the pistons have been superextended due to neglected brake pad replacement, it can take large amounts of force to get them to start retracting.

You can try lifting the dust boot off the piston, and hosing in Silicone Spray to lubricate the dustboot, and the caliper cylinder seal.

You will also need to up the force you are using. Try sliding a 18"-24" of 1/2" or 3/4" diameter black pipe (from the local home center) to the handle of the caliper retraction tool to increase your leverage. You are wasting your time if you're trying to do this with "the cube".

I have an extra pair of rear calipers with a right that has a bad piston (someone used pliers to turn it). The caliper bodies and parking brakes are good. Left side is working fine, does not need to be serviced. The right just needs a new piston. I can even throw in a new caliper seal kit. I will sell them to you and you can install new calipers seals (and use one of the pistons from your old calipers). You can have them for like $50 shipped.

Email me at: [email protected] if interested. Private Message System is not working.


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## DUB-YAH (May 4, 2004)

i am not in need of a caliper i just have a half douzen or so that need to be rebuilt cause they are siezed


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## germancarnut51 (Mar 23, 2008)

If they are seized, you need replacement calipers. Caliper seal kits, only include the dustboot and psiton seal. No other parts are available except for the piston, which is priced higher than a replacement caliper.


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