Cool Carbon front brake pad clunk issue with stock 135i calipers

[1BimmerFan]

Hey guys,

I recently replaced the OEM front brake pads (and rotors actually) on my 135. It was my first attempt at ever changing pads or rotors but it seemed like a pretty straightforward job so figured I'd give it a shot.

I've searched for how to fix what I think my issue is but can't seem to find an answer.

A few days after I did the brake job I was pulling very slowly out of a parking lot with my windows down and when I hit the brakes I heard a soft clunk from the front end. I hit the brakes again and it didn't make the noise but then I reversed direction, hit the brakes again and it made the noise. My only thought was that the pads must be shifting forward/backward slightly when I brake then staying put until I switch directions and they shift again to the opposite side. I took the front driver wheel off and looked at the caliper and think I found what the issue is. There's a couple pics of the area below. Like I said, first time doing a pad replacement so if there are other things I should check or something I overlooked definitely let me know.

Cool carbons are supposed to come shimmed from the factory (which they were) so I tossed my old OEM pads and don't have the old shims. They only thing I've found so far is that people with similar issues did not put a shim or heat shield on the back of the pads but I don't see how that would prevent the shifting issue.

Would really appreciate any help or tips to fix the problem.

[juld0zer]

The shims appear to be present. Your diagnosis is correct - pad shift in the caliper.

[Ginger_Extract]

Normal for aftermarket pads. Every non-OEM pad I've used on this car is like that.

[1BimmerFan]

juld0zer - Thanks for confirming.

Ginger_Extract - Have you ever been able to find a solution? The only thing I can think of is either trying to obtain some shims from the OEM pads and hope they correctly fit over the current pads/shims or fabricating my own custom shims to remove the play.

Any thoughts?

[juld0zer]

The issue is the slightly shorter aftermarket pads and/or thickness and material of their shims. I'll tell you BMW's questionable and contradictive official directive on this issue - they advise against thorough removal of brake dust from calipers and pad contact areas because the build up of brake dust actually acts as a cushion to reduce noise. It's a catch 22 because in their repair instructions they say to clean such areas using non-mechanical methods (eg, brake cleaner spray) and every other good mechanic would clean to avoid pads binding and causing drag.

F2x and F3x Brembos using stock pads are known to clunk at low mileages too.

[HIPSI]

I have CC pads on mine...
45k miles or so, no clunk/quite as can be.
An Indy did the install.

[1BimmerFan]

Hmm, that does seem very sketchy of BMW to have a directive like that. They're pretty much brand new now and I did wipe that area with brake clean and a rag so there's essentially no dust right now. Guess I'll just wait awhile to see if the dust buildup will help at all.

I'm assuming it's not a dangerous issue to have the pad potentially hit into the caliper pretty hard if I were to brake at high speeds?

[titium]

had the same problem with ferodo pads. pulling the backing plates off the old pads and installing them on the new pads fixed it.

not really obvious that the old backing plates need to be reused especially when they are glued on the oem pads....

[Stewy_604]

I have a minor clunk on my MPBK on the X5, I'm running Carbotech 1521 pads. Definitely more noticeable when cold.