[chazzz]

I replaced rear brake pads & rotors (BMW OEM parts only) and when I go in reverse, I hear loud CLUNK in both rear wheels. Didn't have any issues with old brake pads & rotors. Also, I don't hear any clunking sound while driving forward and forward braking.

Do I have "loose" pads? Why are they making noise, only when going in reverse?

Do I need to reassemble the brake pads? Do I need to apply more Quiet Brake paste to the back of each pad?

Any advice or suggestions would be great. Thanks!

[Meeni]

Clunk could also be transmission lash, unrelated to you changing your brakes, incidental that it happened at the same time. Strange but happens. Does the clunk happens when you engage reverse or when you start moving reverse?

Check you have correctly inserted the pads into the pistons (the bizarre three spoke spring that is on the back of the pad).
Rear brakes also contain the parking brake shoes, that you might have disrupted by wiggling in the area. You certainly need to at least remove the wheels and take a thorough look that you still have all bolts and that you respected torque value during reassembly.

[chazzz]

It only happens WHILE pushing the brake pedal. I guess I'll have to remove the pads, clean them up, apply Quiet Brake paste on the back and put them back.

I did not touch the parking brake shoes (didn't clean them), I just leave them alone.

The torque for the bolts holding the calipers is 22 ft/lbs (30 Nm), is that correct?

thanks for your help.

[Meeni]

I have this in my Bentley

Rear brakes:
Caliper to carrier:30NM
carrier to wheel bearing:65NM

wheel lugbolts should torque to 120NM.

Some OEM pads are directional, there is an arrow on the baking plate telling you front and back.

[chazzz]

I've checked the OEM pads to make sure they're directional or not. There is no directional arrows.

I think I probably didn't put enough Quiet Brake paste on the back of the pads. The OEM brake pads in a package came with a paste packet, it's so small, about 1" x 1", I think it isn't enough.

[chazzz]

The caliper mounting bolt is missing, that explains why it was making a loud clunk while braking (while going in reverse). I'm not sure what happened, I think I must have forgotten to tighten the bolt.

Well, I went to the dealer and bought a new bolt. I decided to re-do the brake pads by using CRC brand Quiet Disc Brake (the paste color is orange-red). It's much better than BMW's brake paste (the 1" x 1" packet, came with brake pads from BMW). The little packet is a joke, barely enough to cover four brake pads and it's not "sticky" like CRC brand Quiet Disc Brake.

Well, my problem is solved and I'm happy now. Thought you'd want to know the results.