Technical Brake Pad Shims Query

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Technical Brake Pad Shims Query

bigshorty

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Hi All

In need of a bit of advice on brake pad shims, hoping someone can help me out.

I started changing the front brake discs and pads yesterday evening on my Panda 1.2 Dynamic Dualogic as one disc is warped. I got to the point on the first wheel where I rotate the caliper down to hold the brake pads in place, but no matter what I did there was not enough space for the caliper to sit in it's correct position. With the brake pad shims removed the caliper falls back into place perfectly. I've pushed the piston back as far as I can, filed some of the roughness / grub off the piston mating face, wire brushed the caliper to remove all the caked on rubbish, but I still can't get the brake pads to fit with the shims.

My query is whether I actually need the shims at all? I've read that they are needed, others have said they have run without shims with no problem, I've heard they are good for heat transfer, but also heard their purpose is to silence the brakes.

I'd be grateful if some of you out there could give me your thoughts on what the shims are actually for, and whether it is safe for me to run the car without them. I could run the car for a while, wait for the brakes to wear down a bit first, then that'll give me the space needed to be able to fit them.

Many thanks in advance.
 
Hi All

In need of a bit of advice on brake pad shims, hoping someone can help me out.

I started changing the front brake discs and pads yesterday evening on my Panda 1.2 Dynamic Dualogic as one disc is warped. I got to the point on the first wheel where I rotate the caliper down to hold the brake pads in place, but no matter what I did there was not enough space for the caliper to sit in it's correct position. With the brake pad shims removed the caliper falls back into place perfectly. I've pushed the piston back as far as I can, filed some of the roughness / grub off the piston mating face, wire brushed the caliper to remove all the caked on rubbish, but I still can't get the brake pads to fit with the shims.

My query is whether I actually need the shims at all? I've read that they are needed, others have said they have run without shims with no problem, I've heard they are good for heat transfer, but also heard their purpose is to silence the brakes.

I'd be grateful if some of you out there could give me your thoughts on what the shims are actually for, and whether it is safe for me to run the car without them. I could run the car for a while, wait for the brakes to wear down a bit first, then that'll give me the space needed to be able to fit them.

Many thanks in advance.
You can leave them out no problems in fact some times leaving them out gives better pedal feel.
Some after market pads have 'shim' bonded on or some rubber gunge that's meant to do same job as shim. If your new pads have that you don't need the old shims.
 
You can leave them out no problems in fact some times leaving them out gives better pedal feel.
Some after market pads have 'shim' bonded on or some rubber gunge that's meant to do same job as shim. If your new pads have that you don't need the old shims.

Thanks for the speedy response, much appreciated.(y)

I'll fit them all back together without the shims then (once the rain stops)!!!
 
The shims help to stop brake squeal.


With new pads and discs there should be plenty of space to fit shim as long as the pads don't already have a shim bonded to it?


Often you need to push the piston back in as it will creep back out as you fit the parts. I normally use a screwdriver. But don't go too mad it shouldn't take much pressure and should stop with a solid feel.


Its not dangerous to run without the shim. Often third party garages forget or cant be bothered to fit them. What concerns me is the correct parts should fit together without leaving any parts out.

http://cdn4.pelicanparts.com/techarticles/Mercedes-W204/123-BRAKES-Front_Brake_Caliper_Replacement/images_small/pic10.jpg
 
From memory, the OEM pads on my 2010 Panda 1.2 weren't shimmed (and neither were their aftermarket Pagid replacements). I dismantled them the first week I got the car from new in order to lubricate the reaction frames (this isn't done at the factory).

Properly lubricated, I haven't had a single squeal out of either the OEM pads or their replacements in almost 80,000 miles, despite the absence of shims.
 
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This type come ready to install just peal of the label.


You will see a layer of paste under the paint.
 

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I recently fitted pads and discs to an Alfa Brera. It did not have shims.

If you have a warped disc, check the mounting face is 100% clean and ideally check for run-out. I replaced discs on my last Fiat only to have the same side warp again. The mounting face was not flat.

I solved the problem with thin shims and a dial indicator on the disc outer edge but the issue was actually a duff hub.
 
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