How to disassemble rear calipers?

[Tom F&L GoR]

Yes, I know the manual says they aren't serviceable. So were late '70's Chrysler electric choke resistors....

I'm working on a '94, although all rear calipers up through ABS cars seem to be the same. The dust boots and piston seals are supposedly available at Truechoice (800-388-8783 or 614-876-3483) under PN 20.4872.47 and PN 20.4872.45. My notes say you'll get 4 under each number.

I have the piston unscrewed as far as it will go until it only rotates and no longer comes out of the bore. The manual states there is a snap ring of sorts inside the piston, but I can't get to it. The manual has two cutaway illustrations, but neither with the secret to disconnecting the piston. Anybody know what the magic next step is? Thanks.

 

[GTS Dean]

Tom,

I think Keith Verges got one apart and ended up throwing in the towel on the rebuild. Shoot him a message and he'll fill you in.

 

[Hoosier Daddy]

Give Parts Rack a call if you need one. Luckily these don't get wrecked in wrecks!!

 

[FrankBarba]

i was working on rebuilding the rears on the 95 green machine.
yes there is a snap ring and it is a pain in the A$$. I threw in the towel also. Parts rack was great in helping me out. When you believe the rears have gone buy replacements. as i contacted the techs and others that appear on this board, the concensis was
"you did what?" "You my friend are in uncharted territory"

 

[kverges]

Very, very tricky. The seal kit is available and the caliper can be rebuilt, but reassembly is a major pain. The parking brake actuator mechanism is fairly complex. It has been a while, but on the side of the caliper is an access hole with a recessed allen bolt that acts much like a set screw. It basically locks the internals together. I want to say that you remove that part, then essentially unscrew the piston all the way and go from there. I highly recommend trying to find a used caliper to practice with, as I made a bit of a mess my first time (in fact I finally found used calipers and they are on my car). Pay super close attention as things come out in order to properly reassemble. I can't even tell you where to get the seal kit, as I got mine through the now defunct carparts.com. This caliper comes from another Dodge or Chrysler vehicle, I think, and I would see if rebuilt calipers are available for it. It can be done, but be prepared to spend a considerable time fiddling about. There is an internal C-clip that must be engage blindly by assembling the whole works at once.

It can be done, but I'd spend some time looking for reasonably priced replacments. Last time I checked, the Calipers were on the order of $500, so it is worth it to fiddle about.

 

[Frank Parise]

I have 4 used stock rear calipers...one set with less than 1000 miles, the other set with 5,000 miles. Both were used on the track before I upgraded my brake system. You can have all 4 of them for $400. E-mail me if interested.

 

[Tom F&L GoR]

Well, they do come apart after all. I removed the driven disc stop allen screw, although I don't think that's needed. Once the piston is unscrewed enough to disengage from the worm shaft, there is a crude internal snap ring (looks like coat hanger wire in a nearly complete circle) that seats in the piston. It holds the "driven" disc on the worm shaft captive inside the piston, which is why the piston wouldn't just keep coming out. Simply pry up on the piston, the snap ring compresses and the piston pops off. (Surprise!) The parking brake mechanism stays inside the caliper. Lots of washers, springs, and other gizmos inside... If I can get it back together, I'll take a few pictures of the complete procedure. They should be rebuildable, with only a few more steps than a normal caliper. Rear seals and boots were supposedly $4. Hey, there's only one piston, how hard can this be?