[Patel151]

Is there a chance that a batch of Zimmerman rotors could be defective with different part numbers? My rears started making basically the same exact noise as the fronts when I had the new rotors on and now I can’t figure out what’s going on. When you push in the brake, the same pulsating effect can be heard until you fully let go off the brake in the rears which is weird because it was fine the past few weeks and all of a sudden yesterday the problem is in the rears this time.

[Polo08816]

Originally Posted by Patel151

Is there a chance that a batch of Zimmerman rotors could be defective with different part numbers? My rears started making basically the same exact noise as the fronts when I had the new rotors on and now I can’t figure out what’s going on. When you push in the brake, the same pulsating effect can be heard until you fully let go off the brake in the rears which is weird because it was fine the past few weeks and all of a sudden yesterday the problem is in the rears this time.

I'm wondering if there's an issue in how they were manufacturered.

So at the last NCC DIY, someone brought Zimmerman rotors they bought from FCP Euro. The part numbers and SKU on the Zimmerman rotor packaging was correct for his vehicle, but the rotors clearly didn't fit his X5. We suspected that Zimmerman packaged the wrong rotor in the box and there was no way for FCP Euro to anticipate that error.

The quality across all parts manufacturers seems to have gone down.

[Antoshka_tony]

Is this the same situation here? Though, i’m not braking in the video. It used to appear when i enter parking lot, turning the wheel 45’ and slowly riding. Now it took place during slow straight

https://youtube.com/shorts/OJUuCwthOeY?feature=share

[Oksamit78]

Originally Posted by Antoshka_tony

Is this the same situation here? Though, i’m not braking in the video. It used to appear when i enter parking lot, turning the wheel 45’ and slowly riding. Now it took place during slow straight

https://youtube.com/shorts/OJUuCwthOeY?feature=share

If you are not braking and sound is there - it is related to your drive shafts or wheel bearings, or any other component that is related to wheel rotation. The frequency of the knocking sound on your video is proportional to the speed of your car.

[Patel151]

The warranty is still being worked out for the new rotors. I measured the new rotors and they are pretty much the correct size and they are identical to the old rotors. So, maybe the build quality has a defect. The supplier did send me the correct rotors for my car though. The old setup in the front is working fine for now, no weird noises.. but doesn't have much life left.

One thing I noticed is the new rotors have some sort of indented lip and each rotor has a different size indentation. Is that normal? I don't see how that would affect the braking though.

[Polo08816]

Originally Posted by Patel151

The warranty is still being worked out for the new rotors. I measured the new rotors and they are pretty much the correct size and they are identical to the old rotors. So, maybe the build quality has a defect. The supplier did send me the correct rotors for my car though. The old setup in the front is working fine for now, no weird noises.. but doesn't have much life left.

One thing I noticed is the new rotors have some sort of indented lip and each rotor has a different size indentation. Is that normal? I don't see how that would affect the braking though.

I wonder if the amount of material removed from that area is used to "balance" the rotors.

[Cesarherc]

You know I been having a similar issue, not sure if that’s the case with you, I had this annoying clunk every time I depress the brakes, it’s only in the front tho, I think for me the brake pads are the issue, they are possibly just rattling around even tho I put the proper lubricant, what I recently did is I changed the rotors to the Zimmerman brand, I changed the slider pins and put new anti rattle clips, it’s cleared up about 50 percent of the clunk, but it’s still there, my problem was that I got autozone brake pads, im actually gonna buy some oem ones and replace them again, but what I would check is the brake pads themselves if you have a clunk.

[charlie fairmont]

Not sure if these will solve any of the issues in this thread but they seem like a cheap and easy option to try.

https://www.bimmerworld.com/Brakes/B...xoCXFgQAvD_BwE

[Polo08816]

Originally Posted by Cesarherc

You know I been having a similar issue, not sure if that’s the case with you, I had this annoying clunk every time I depress the brakes, it’s only in the front tho, I think for me the brake pads are the issue, they are possibly just rattling around even tho I put the proper lubricant, what I recently did is I changed the rotors to the Zimmerman brand, I changed the slider pins and put new anti rattle clips, it’s cleared up about 50 percent of the clunk, but it’s still there, my problem was that I got autozone brake pads, im actually gonna buy some oem ones and replace them again, but what I would check is the brake pads themselves if you have a clunk.

I suspect you have an issue with either your control arm bushings or your sway bar endlinks.

[Cesarherc]

Unfortunately I’ve already changed both of those parts, actually the only thing that’s left in the suspension that is still original is the sway bar itself and the bushing aren’t bad, I actually had even went as far as removing the end links and took it for a test drive to see if it was the sway bar but the clunk was still there, I’m more confident that it’s in the brake system, like I said I changed the slider pins and the rattle clip and it actually help reduce the sound, the calipers seem to move properly, not getting stuck or rusted, ima change the pads soon, I already ordered them, luckily autozone was able to exchange them, the absolute last thing I can think of is maybe some air in the brake fluid? I changed the fluid as well, maybe I didn’t bleed it right, but I’m not sure if that would be any reason to get a clunk you know, anyways once I put the new pads on I’ll post my results lol

[casualDIYer]

Originally Posted by Polo08816

Is this even necessary on the Brembo M Sport Brake option?

Not according to BMW's instructions.

As for why these items need to be replaced every 4 years (according to BMW). 1) The pins will warp over time making them hell to get back in and 2) the spring does lose it's springiness being less effective over time.

I too am a Hawk user, with the 5.0 on the street and HP+ on the track. Not a surprise to learn the HP+, while still doing well for a track day pad, have been cut down quite a bit. When the brake is applied I can hear the clack of the piston hitting the pad. Never had an issue with it.

[casualDIYer]

Originally Posted by Cesarherc

Unfortunately I’ve already changed both of those parts, actually the only thing that’s left in the suspension that is still original is the sway bar itself and the bushing aren’t bad, I actually had even went as far as removing the end links and took it for a test drive to see if it was the sway bar but the clunk was still there, I’m more confident that it’s in the brake system, like I said I changed the slider pins and the rattle clip and it actually help reduce the sound, the calipers seem to move properly, not getting stuck or rusted, ima change the pads soon, I already ordered them, luckily autozone was able to exchange them, the absolute last thing I can think of is maybe some air in the brake fluid? I changed the fluid as well, maybe I didn’t bleed it right, but I’m not sure if that would be any reason to get a clunk you know, anyways once I put the new pads on I’ll post my results lol

Air in the brake fluid will not make a clunk. It will ruin the ability for the car to stop, especially under hard braking. I guess depending on where that happens, there will be a clunk . . . . as your car smashes into something.

As mentioned, clacking pads are not unusual as they wear down and the space between the pad and rotor gets bigger. A new set should eliminate this issue. If you had put in new pads and they ran down rather quickly, you've discovered a crap brand/model of pad. From what I've seen, the cheapo (~$20 per pair) pads actually work fine for city driving. Where they fail is under hard braking e.g. an emergency stop where they tend to disintegrate rather quickly. You could be out driving for weeks using little pad then have one incident where you hammer the brakes really hard and consume 25% or more of the pad. Cheap pads tend to live much shorter lives than the premium makes and models as the cardboard in them doesn't last long.