2001 Boxster S front brake shims

[mesutter]

After reviewing online videos, the Boxster brake pad replacement process seemed simple and straightforward, so got new pads and began the task. Something immediately seemed wrong. Whereas in the video, the old pads were easily withdrawn after removing the pins and spring retainers and retracting the pistons, mine wouldn't budge. Looking closely, it looked like my pistons were stuck to the pads (and mighty small pistons they were, strangely). A bit of research revealed, of course, that I was looking at the locating buttons on the shim plates, p/n 996 351 088 02. The videos I watched obviously were of a base Boxster that does not use shim plates. That brings up several questions:

1. What the best method of freeing the plates from the pads, or should I simply remove the calipers and extract the pads and shims as a unit?

2. Are the shims needed (do they do their job of keeping the brakes quiet)?, and if so, can I re-adhere the old shims to the new pads (what adhesive will withstand the heat)?

3. What's the downside of eliminating them entirely and simply using an anti-squeal compound as I have done on all the other cars I've owned? (I know, a Porsche is not any other car). The cheapest I've been able to find the shims for is $40 for a set of four. Few pad sets come with them, evidently, nor do the websites selling the pads have a "you may also need" reference to the shims.

I've searched the forums, and strangely, the issue has never been fully addressed on this forum, as far as I can determine. On another forum, some claim that shops routinely omit them, and the claims of their effectiveness is all over the map. One commenter mentioned that he leaves them out so that he can quickly change his pads from street to track.

Any and all knowledgeable comments will be much appreciated!

Edited November 25, 2015 by mesutter

[timbo]

Well if it helps I have  2000 2.7 which I have had for 7 years and 60k miles, it doesn't have shims and the brakes have never squealed, From what I can recall I dont think they are glued to the pads.

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[mckinlay]

2000-2001 Base Boxster don't use the shims and after setting the caliper pistons back will usually lift out by hand.  The Boxster S does use them and they have an adhesive that adhears to the back of the pads.  I take a thin putty knife and slide (which usually means force) it down between the pads and the shims.  Once you break them loose, the pads will lift out and once the pads are out you can simply lift out the shims.

 

The Porsche manual calls for the shims to be replaced when you replace the pads.  I usually don't and I have had no apparent issues.  Brakes work great and I have no squeal.  When I go back to replace the pads, the shims have readheared to the pads.  I think the heat and the pressure must reset the adhesive. 

 

I know others who just don't use the shims and also have no problems.

[mesutter]

...I take a thin putty knife and slide (which usually means force) it down between the pads and the shims. 

 

The Porsche manual calls for the shims to be replaced when you replace the pads.  I usually don't and I have had no apparent issues.  Brakes work great and I have no squeal.  When I go back to replace the pads, the shims have readheared to the pads.  I think the heat and the pressure must reset the adhesive...

Thanks! I think I'll try the re-use approach. Separating them while in the calipers seems like a good approach, as they are firmly held In place. If I remove them as a unit, I would likely have to clamp the unit in a vise.

I am planning to use Akebono ceramics, as my usual choice, PBR/Axxis are currently not available. The Akebonos appear to have a shim plate clipped to the pads. Does anyone know if that plate is designed to be used in lieu of the Porsche plate on in conjunction with it?

[mesutter]

Topic is moot at this point. Someone pulled out out a driveway directly in front of me on a city street tonight (on my way to pick up brake pads!) and we collided. The right front corner is a complete mess, so next week the insurance company will have to determine if it is a total loss. See attached photo. The only body panels damaged are the fender and bumper, but I'm certain the whole right side suspension is toast and there is likely significant structural damage.