135i brakes clunking before and after pad change

[str8shot]

I've got a 2008 135i with brembo 6 pots.

I recently changed out the Hawk DTC pads that were installed by the PO in favor of some Hawk HPS flavors.

My question is - in the morning, or after the car has sat, the first brake pedal push causes the pads in the front to clunk loudly.

Almost like they've settled and they're being forced back into position.

Any one know the cause and remedy for this situation? The pads have the Hawk shims that were pre-installed from Hawk.

[My135]

I guess it is normal. I and other people experienced the same problem with after market performance brake pad. It is due to the fact that they are marginal smaller (not an exact fit) than OEM.

[Dackelone]

Sounds like your pads are moving around in the caliper. Did you buy new spring clips? Maybe shimming up the pads might help too.

[Focusedintntions]

It's due the fact that they don't have backing plates on them. To keep them from clunking you're supposed to peal off the backing plates of the oem pads and transfer them. This is a very common issue with people that switch to hawk pads. Cool Carbon pad don't have this issue b/c they have new backing plates.

[GaryS]

Sounds like you need the OEM backing plates.

edit: haha Focused typed all that faster than I could type eight words.

[Wings0fRed]

Originally Posted by Focusedintntions

It's due the fact that they don't have backing plates on them. To keep them from clunking you're supposed to peal off the backing plates of the oem pads and transfer them. This is a very common issue with people that switch to hawk pads. Cool Carbon pad don't have this issue b/c they have new backing plates.

Been using Cool Carbon pads and haven't had the issue at all - as stated they already come with some backing plates.

[My135]

Any other side effect other than the clunking noise?

[GaryS]

Originally Posted by My135

Any other side effect other than the clunking noise?

Yes, the OEM backing plates insulate the calipers from the heat. The temp problem is so bad, lots of people add titanium plates for even more protection.

[Focusedintntions]

Originally Posted by GaryS

Yes, the OEM backing plates insulate the calipers from the heat. The temp problem is so bad, lots of people add titanium plates for even more protection.

This is only for track purposes...on the street no other issues.

[str8shot]

What's the backing plate look like?

The hawks appear to have backing plates on them already?

At least the same as any other brake I've changed out before (on other cars).

Am I missing something?

[Hambone]

I just put Hawk HPS pads on my car the other day as well and am having the same problem. It's mostly just when I'm switching from reverse to forward and vice vesa. But these pads came with back plates on them already, so I'm wondering if taking the plates that came on them off and putting the stock plates on them would fix the issue?

[Xaeryan]

Originally Posted by str8shot

What's the backing plate look like?

The hawks appear to have backing plates on them already?

At least the same as any other brake I've changed out before (on other cars).

Am I missing something?

Terminology clarification required here:

All pads, aftermarket or OEM, have backing plates. It's what the pad compound is fused to, as you probably already know.

The missing piece on some aftermarket pads (i.e. Hawk) being discussed is a thin metal anti-squeal/rattle plate that comes on the OEM pads. (Backing plate is a misnomer even I've used when describing this removable piece) It wraps around the sides of the pad's true backing plate, so it adds to the width (it's thin; around .75mm I'd estimate). You can make it out a bit here, it's the part with white text printed on it: https://www.carpartsdiscount.com/aut...ml?3593=265026

Without it, the OEM pads (or other equally sized aftermarket pads) will have some play encountered, particularly on the first reverse of direction. According to Hawk, this is normal and their pads are designed without these metal plates to allow for heat expansion... take that for what it's worth. :-\

[Hambone]

The Hawk HPS pads that I just put on the other day had those metal plates on them and still clunk. I'm going to try taking them off and putting the metal plates from my old stock pads on them, though, and see if that helps. I'm thinking that the Hawk metal plates are slightly thinner than the OEM metal plates.

[Xaeryan]

Originally Posted by Hambone

The Hawk HPS pads that I just put on the other day had those metal plates on them and still clunk. I'm going to try taking them off and putting the metal plates from my old stock pads on them, though, and see if that helps. I'm thinking that the Hawk metal plates are slightly thinner than the OEM metal plates.

Probably the case. The HP+ pads for the 135i do not come with these at all, so there's an even larger gap.

[str8shot]

Originally Posted by Hambone

The Hawk HPS pads that I just put on the other day had those metal plates on them and still clunk. I'm going to try taking them off and putting the metal plates from my old stock pads on them, though, and see if that helps. I'm thinking that the Hawk metal plates are slightly thinner than the OEM metal plates.

The Hawk HPS have an anti-rattle shim plate preinstalled from Hawk.

It looks exactly the same as the oem shims, so I doubt thats the problem.

I'm thinking it might be the spring...

[135IS]

i jsut installed hawk pads i have the same problem apparently its normal...

[Hambone]

Originally Posted by str8shot

The Hawk HPS have an anti-rattle shim plate preinstalled from Hawk.

It looks exactly the same as the oem shims, so I doubt thats the problem.

I'm thinking it might be the spring...

The springs didn't feel worn, and I don't see how the springs provide forward/backward support which is where this issue is happening - forward and backward slippage of the brake pads. I'm going to play around with them some tomorrow and see what I can figure out. I'd rather have squealing brakes than clunking brakes. It's kind of embarrassing pulling in/out of a parking spot with someone in your car and your vehicle sounds like it's falling apart.

[Pig Farmer]

This clunking is common as you move toward a track focused pads. They are made slightly smaller to account for heat expansion on the track. The pad material may be slightly thinner as well depending on how much the pad material resists compression.

[1&done]

I added titanium shims and the noise has stopped for me

[str8shot]

Originally Posted by Pig Farmer

This clunking is common as you move toward a track focused pads. They are made slightly smaller to account for heat expansion on the track. The pad material may be slightly thinner as well depending on how much the pad material resists compression.

I don't agree with this. Any pad gets thinner as it wears...because one starts out thinner shouldn't make a difference.

It should be compensated the same way it would be if the pad had worn down to that thickness.

I've got Ti shims I need to reinstall. We'll see if that makes a difference, but I doubt it. It's gotta be something else.

[Focusedintntions]

It's not b/c the pads are thinner...they aren't...they're slight shorter. The clunking you hear is the backing plates sliding up and down within the caliper and stopping. If notice on oem and cool carbon backing plates the reach around the edges you almost have to wedge the pad in the gap. The Hawks don't have this edge buffer which allows them slide up and down within the caliper and you reverse and move forward. This really isn't rocket science as to why they clunk.

[My135]

Where I can buy the titanium shimes for my 135? Thanks for helping in advacne.