1990 964 - Difficulty with removing brake pads

[Bedo]

Any suggestions on how to remove stuck brake pads? I've separated the pads from all four dampers using a thin steel spatula (they now move back and forth between piston and caliper when pried with a screw driver), but they're not coming up (out) when tugging or prying... at all.

[Arrowhead]

You probably have anti squeel cups installed and if so you will have to remove the caliper with the bracket as a unit so it slides over the rotor. Then the pads will come out with the anti squeel cups attached. Or you have a very large lip on the outer edge of the rotor due to wear and someone forced new pads in there.

[nickd]

This is not going to be good news-

You almost undoubtedly have the typical aluminum corrosion beneath the steel spring plates above and below the pads that keep them snug. The only solution is to pull off the calipers and remove the spring plates to get at the corrosion. I would highly recommend shipping them out to have this done as the spring plate screws are cemented in with some amazing locktite and need an acetylene torch to get them out without destroying them.

The new pads will bind the first time you use them if the corrosion is bad enough- and it doesn't seem to take much (been there...).

There are a number of rennlist threads on the subject. A search for "caliper spring plate" will give more info. Good luck!

[PNine64]

IDK, I really think Arrowhead was on the right track with his comment below.

Originally Posted by Arrowhead

You probably have anti squeel cups installed and if so you will have to remove the caliper with the bracket as a unit so it slides over the rotor.

That said, I'm not sure that you have to take off the caliper to take the pads out. You can separate the anti squeal / mushroom / spider whatever they are called from the back of the pad with the caliper in place and slide the pads out (and then the anti squeal device). Here is an exchange on RL discussing the nest steps...installing new pads and how to mitigate squeal (although there are tons of these and mine still squeal ). HERE

[cjoenck]

You are missing Bedo's point, I believe. He said that he "separated pads from the dampers" or whatever you call them. Reason they are not coming out could be:
- because of excessive wear of rotor as stated above
- Corrosion under the spring plate and someone modified old pads to compensate

I would pull the caliper - actually pretty easy to do - to get better access. You don't have to disconnect the breaklines for this.

[TMc993]

Originally Posted by cjoenck

I would pull the caliper - actually pretty easy to do - to get better access. You don't have to disconnect the breaklines for this.

That's what I'd do, but if you don't disconnect the brake line, it'd be a good idea to have a second set of hands around to assist.

[B. Elliott]

Have you tried removing the entire caliper at all?

[911jettat]

Originally Posted by PNine64

..........That said, I'm not sure that you have to take off the caliper to take the pads out. You can separate the anti squeal / mushroom / spider whatever they are called from the back of the pad with the caliper in place and slide the pads out (and then the anti squeal device).

I hope these pictures help...

caliper through pad pins and clips

[Bedo]

Thanks for all of the input guys - your comments have been very helpful.

After completing the following...
• buying a slide hammer and managing to remove all 8 pads
• cleaning everything up with brake cleaner and a wire brush
(I avoided the pistons)
• replacing all four brake pad wear sensors
• replacing all 16 Dampers
• slightly filed the pads for the two stubborn locations then repainted the raw metal with a similar epoxy paint
(not sure where I stand with 2011 tax returns yet)
• putting a light coat of Permatex anti-corusion paste on the contact "rails" (only) of all of the pads
• breaking-in the pads with a test run (it brakes straight, quiet and stronger with no shimmy)...
I have one remaining piece of the puzzle to solve.
The brake pad warning light on the dash still lights up!

I was very careful to make sure that all of the sensors were seated correctly to both the wring harness and pads. Is there any technique for resetting the signal? I cannot find a relay, so perhaps pulling the allocated fuse will do it?

Any thoughts would be greatly appreciated. Thanks again.

[911jettat]

I haven't had any luck installing pad sensors (or reusing old sensors)...so I followed this technique to bypass them:
Ditching the brake pad wear sensors: Ditching the brake pad wear sensors

(with the sensor disconnected you'll have to monitor brake pad wear)

[PNine64]

There is no resetting the system. When you fix it the light will go out. I did like jetta and zip tied mine up out of the way (although not bypassed). I would double check your connections.

[Bedo]

Job's Finished

I made the mistake of attaching the sensor wire to the wrong (empty) port on the wiring harness for the front right brake. I'll sleep better now. Thanks again for all of the input everyone. B.