Are brake pad shims really needed?

Hello All, I've seen a few threads about folks replacing brake pads and wrestling with disintegrated shims that are still stuck inside the piston, etc.. Now, I'm experiencing the same thing when replacing my pads. The left-rear brake assembly was in generally good condition, except the pads were shot, of course. The pads came out easily, and the shims inside were in great shape. So I was planning to reuse them. However... when I went to the right-rear brake assembly, things were different. The worn pads came out easily. But, the shims that fit into the pistons were horribly rusted to pieces. So in this circumstance I have to replace them. So my question is do I really need to have shims there in the first place? I've replaced many pads over the years that only have that thin, tape-like anti-squeal tape that comes already on the pad. The new Textar pads I purchased have that aforementioned tape already on the back of the pads. Has anyone removed the slip-in shims and noticed any difference? Or, is there someone out there with more knowledge than me that knows that I really should have them installed? Thanks much, Steve

I don’t think you will need them my car came with OEM rotors and Pagid pads , after few years started creaking but the brake power was always there so I disassemble the whole thing to service and lube moving parts and noticed o don’t even have shims. I’m no mechanic just a DIY er, I’ll leave it pros to respond

It’s strange that one side was rusted and degraded far more than the other, do they salt where you live? Anyhow that plate with the hats that press into the caliper pistons is for anti vibration according to what I could locate on the subject. Certainly the brakes will perform without it, however when I did this job last year, I put new ones in. They are inexpensive and my way of thinking is Brembo engineers know more than me so I replaced them.

Yes lots of salts during winter. I don’t daily during winter and every now and then when it’s dry I drive it but still salts everywhere! The rising having shims stuck is when you want to remove it you might accidentally damage cylinder’s rubber boot.

The shims are there to reduce brake squeal. Reports are that they help. You may be able to just use some anti-squeal spray or paste on the back of the pads for the same effect if you leave them out. They shouldn't affect braking performance.

I've gone down this road with my 2012 CSBE 60k miles or so. I use a copper based anti seize on the pad back with acceptable results, no squeaks or squeals. Of course I'm not a Porsche engineer, but I find those shims to be a bit odd. There's the shim material as well as the cylindrical part that sits in the piston. Seems a bit complicated or overkill, but maybe for track use they help dissipate heat?

I believe it would be Brembo more than Porsche unless they specify the build to Brembo . LIke Gubi I read for vibration and anti squeal. Never been in salt so it’s not an issue but I’m sympathetic to the idea that in salt environments they may not be ideal because all the wrenching I ever knew was in CNY where new advancements in salt adhesion make corrosion even worse than it ever was, taking out brake lines and more. I used to clean my brakes every spring on the cars I wintered for similar reasons.

Thanks for all the comments. My other calipers and shims seem fine, so I'll just replace the destroyed ones. Plus, Pelican was having a sale on those rear shims, so I took advantage of that. As I recall, my old '02 C4S did not have any unique shims like the Cayman does, and I drove the wheels off that one without any issues with squeaks/vibes, etc.. So maybe by '06 Porsche engineers must have learned something new. Thanks,

Most cars don't have them. As far as I can tell the only purpose is to stick the pads to the pistons to avoid the vibrations that cause brake squeal. The pads most European cars use seem more prone to squeal and US drivers seem to complain more about squeal (it's an item in the JD Power quality surveys IIRC) so Porsche probably added them to reduce NVH complaints. Like I said, if you don't care about squeal or don't have it I'm sure you can leave them off. There are also various products sold that do the same thing: basically you spray/spread them on the back of the pad and they tack the pad to the piston. But manufacturers these days will generally go with a pre-applied solution like the shims since it's easier to ensure the job was done correctly (see also: bolts that come with loctite pads on them vs. manually applying loctite ). All that said, personally I just installed new shims when I did my brakes because, whatever, they probably help.

On my previous '08 987CS I replaced front brakes at ~70k miles with Textar front pads , hardware, Zimmerman Z Coated disks , Sebro sensors . OE Front pads were at eight 32's at time of replacement, rears were at about seven 32's and were not replaced. I did not use/replace OE shims because new pads came with their own version. Kept car for another 20k miles and experienced zero problems with brakes or squeal.

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