Rear brake caliper rebuild Question, Can't figure out exactly how to tear down |
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Rear brake caliper rebuild Question, Can't figure out exactly how to tear down |
Mikey914 |
Aug 24 2006, 08:26 PM
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#1
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The rubber man Group: Members Posts: 12,678 Joined: 27-December 04 From: Hillsboro, OR Member No.: 3,348 Region Association: None |
Well I've got all of the easy part done. Actually the P/O tried to rebuild and the leak appears to be from the e brake actuator. How do I get this thing apart? the only thing left to do is remove the plug, but I didn't want to do it unless I have to.
The piston in this side is stuck in, I tried to pry lightly, but didn't want to put too much pressure on it incase there's something I might break. If anyone has any reference material the Haynes manual glosses right over this. Any help would be apreciated Attached image(s) |
SLITS |
Aug 24 2006, 08:41 PM
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#2
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
Check or search Eric Shea's posts.....he did a blow by blow essay on rebuilding the rears. Haynes and Porsche will tell you it can't be done.
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KenH |
Aug 24 2006, 08:52 PM
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#3
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Senior Member Group: Members Posts: 680 Joined: 16-January 03 From: Gilroy, CA Member No.: 156 |
The leak is NOT from the E-brake, There is an O-ring on the adjuster screw that keeps fliud from escaping in that direction. You must remove the adjustment screw. It is held in place by a cir-clip at the bottom of the piston bore. You have to split the calipers to get to it.
Ken |
Mikey914 |
Aug 24 2006, 10:39 PM
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#4
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The rubber man Group: Members Posts: 12,678 Joined: 27-December 04 From: Hillsboro, OR Member No.: 3,348 Region Association: None |
So, there is nothing that holds the piston in on the side that has the e-brake actuator? right?
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Lou W |
Aug 24 2006, 11:58 PM
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#5
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"Here Kitty Kitty" my ass...... Group: Members Posts: 4,109 Joined: 9-May 04 From: Roseburg, OR. Member No.: 2,039 Region Association: Spain |
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KenH |
Aug 25 2006, 12:10 AM
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#6
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Senior Member Group: Members Posts: 680 Joined: 16-January 03 From: Gilroy, CA Member No.: 156 |
Not sure how to say this. The fluid/hydrolic movement of the piston is isolated from the Ebrake mechincal actuation. There is no fluid where the Ebrake actuator enters the caliper body. The 5mm hex adjuster rotates a shaft that sets the pistion position. There is an o-ring on the shaft where it enters the pistion bore. The o-ring keeps the fluid from leaking out. The Ebrake actuator pushes on the outside end of this shaft, which slides in/out a bit, in turn it pushes the piston against rotor. It also displaces some oil causing the inside piston to clamp as well.
Ok - or is this even more confusing?? Ken |
Eric_Shea |
Aug 25 2006, 12:44 AM
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#7
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PMB Performance Group: Admin Posts: 19,278 Joined: 3-September 03 From: Salt Lake City, UT Member No.: 1,110 Region Association: Rocky Mountains |
QUOTE Ok - or is this even more confusing?? You're confusing me. (IMG:style_emoticons/default/wink.gif) (IMG:style_emoticons/default/biggrin.gif) The seal on the e-brake arm can go bad. They come in a seperate kit that's $49.00 (read: more than a good core is worth). That kit includes a 25mm side (welch) plug as well. QUOTE The piston in this side is stuck in, I tried to pry lightly, but didn't want to put too much pressure on it incase there's something I might break. It's probably not stuck. It is on a threaded adjuster. The picture you show in your first post shows a missing rear adjuster cover and you're probably missing an inner adjuster gear. Look at the back of the caliper. Look down the hole. Is there a 4mm (not 5mm) adjuster gear down there? It should slide out with some light taps... the problem is, it's probably already slid out and gone missing. Once you find or source this gear, you drop it down that shaft and turn clockwise with a 4mm hex key. Your piston will begin to push it's way out. It has about 1/8" to go once it's off the adjuster. This is where you want to put it in a soft vise and wiggle the caliper 1/2 off the piston. Once you get the piston out you'll see the adjuster shaft and a small clip. Put saftey glasses on because brake fluid is about to splatter all over your face. Take a straight dental pick and with your thumb over the top of the adjuster, pry inward (toward the shaft) and upward on the clip. It should snap out and send parts flying which is why I told you to put your thumb over the end of the adjuster shaft. Once the clip is out you should be able to slide the entire adjuster mechanism out and get at the seal Ken is talking about. Clean everything up and put on a new o-ring seal (it's at the base of the shaft just above the gear teeth. Next you have to get it back in... see the link and thread above. You'll need a 12mm deep well and a decent size clamp. If you have any questions, ask them in this thread and I'll get back to you (you could PM me but then others won't learn anything) (IMG:style_emoticons/default/wink.gif) Hope that helps. |
Eric_Shea |
Aug 25 2006, 12:49 AM
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#8
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PMB Performance Group: Admin Posts: 19,278 Joined: 3-September 03 From: Salt Lake City, UT Member No.: 1,110 Region Association: Rocky Mountains |
BTW...
Posts 6 & 7 (in the link Lou posted) show the clip and the o-ring on the adjuster (respectively). |
Eric_Shea |
Aug 25 2006, 12:54 AM
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#9
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PMB Performance Group: Admin Posts: 19,278 Joined: 3-September 03 From: Salt Lake City, UT Member No.: 1,110 Region Association: Rocky Mountains |
Here's a (bad) picture of the gear you're probably missing...
Attached image(s) |
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