BMW M4 F83 Brake Calliper failure

[DavidOz]

Hi folks!

Looking for opinions on this subject regarding a failed right, rear calliper.
1 of the torx bolts - I think its called - failed, sheared off & meant the calliper was damaged.
Luckily I stopped & avoided further damage.

Before the car was towed, I took images of the wheel, disc, calliper etc. They actually look pristine!!

BMW called me today to say, yes the bolt(s) need replacing, as does the calliper, but now also the entire disc?!
Additionally they were suggesting I should consider replacing both rear callipers.
Im getting “nervous” about this as it seems unnecessary - perhaps “best practice” which I understand, but not necessary.
I say “nervous” as I sense this may be being viewed as an easy charge to me the customer, when its not all necessary.

Im surprised as the roadside assist mechanic, inspected everything he could, and the disc looks brand new. No score marks, indentations, super straight. Nothing.
I travel 4,500kms (2,800 miles) annually - you cab appreciate the brakes are in excellent cond for a 3-4 yr old car.

What are your opinions - if you have experienced similar?

Very interested in hearing from you.

[AlmondJayRoM3]

Ask the service advisor why they think each part has to get replaced. If they don’t give you a good enough explanation, get it checked out by an independent mechanic or another dealership if you don’t trust them. Sheared brake bolts happen but it’s rare on a car that isn’t old, corroded and normally driven. Now if the car has seen a lot of track time, perhaps with excessive heat cycling and overheating, the bolts or other brake components can weaken. You can sometimes tell the brake calipers have overheated if the blue paint has discolored.

As for me, my 51000 mi 2016 F80 has seen occasional track time, on my second set of front rotors and third set of brake pads. I’m almost due to replace the front pads again and it’s a crapshoot on whether I have to replace the rotors.

[DavidOz]

Originally Posted by AlmondJayRoM3

Ask the service advisor why they think each part has to get replaced. If they don’t give you a good enough explanation, get it checked out by an independent mechanic or another dealership if you don’t trust them. Sheared brake bolts happen but it’s rare on a car that isn’t old, corroded and normally driven. Now if the car has seen a lot of track time, perhaps with excessive heat cycling and overheating, the bolts or other brake components can weaken. You can sometimes tell the brake calipers have overheated if the blue paint has discolored.

As for me, my 51000 mi 2016 F80 has seen occasional track time, on my second set of front rotors and third set of brake pads. I’m almost due to replace the front pads again and it’s a crapshoot on whether I have to replace the rotors.

Whoooooaaa! 51000 miles? Thats great + tracking it. Nice!!

Thanks for your reply. I cant drive it to another dealer - and getting an independent mechanic is certainly good advice.

I think part of my frustration is I don't understand in depth mechanical & technicals - so a service adviser may be able to pick up on my lack of knowledge.

I sure can ask... why does part X need replacing...why does part Y need replacing.
Case in point...I asked the adviser earlier about the disc. Why does the disc need replacing? The response was “Its damaged”.

Its hard for me to to argue the point - unless I send them the images I took before I had it towed.
I swear the thing is spotless.

Thanks for your sharing though - appreciate it.

[MisterF80M3]

It does seem excessive to replace both calipers and rotors. The dealer might be expecting a failure of the other caliper, which is why they are recommending replacement of both.

Honestly, if the other caliper and both rotors are fine, I would just replace the caliper only.

[dvq]

You said one of the torx bolts sheared? This is a CCB brake caliper and rotor?

[icebiker]

I'd challenge the dealer to show you specifically where it is damaged, then show him/her the pics you took to see if that "damage" claim is still valid. At my dealer, they do a video walk around of the car on the lift before doing any work so they can show me the current condition. It's a way to be transparent between owner and service department. Good luck!

[rmanm4]

If its the caliper bolt that is damage (this is a slider bolt) then its not going to damage anything. You just replace that bolt. I would ask for the part number of the bolt that broke off from the SA and post it here. We can look it up and see exactly which bolt it is and how it would effect the caliper. I have a feeling your dealership is trying to squeeze you. If you are out of warranty, you should take it to the a indy shop with good reviews.

[PhatLyfe]

Originally Posted by icebiker

I'd challenge the dealer to show you specifically where it is damaged, then show him/her the pics you took to see if that "damage" claim is still valid. At my dealer, they do a video walk around of the car on the lift before doing any work so they can show me the current condition. It's a way to be transparent between owner and service department. Good luck!

That's awesome, which dealer is this?

[VChenz]

Did the sheared head of the bolt fall between the rear disk and heat shield? If so, that would cause the disk to score and render the disk trashed. You wouldn't be able to see that damage unless you removed the disc from the car.

I'm surprised the caliper needs replacing. Unless theres something Im missing. The caliper should be 100% fine as the torx bolt connects the caliper to the knuckle. It has not impact on the operation of the brake. Did they foresee damaging the caliper when drilling out the torx bolt from the knuckle?


It's hard to say without pictures. But get pictures of the damage. Replacing the other side seems like an absolute money grab. I can understand replacing both rear pads and rotors as a set but even that is a bit of an industry lie as I don't believe brakes work less as they wear (unless you get a badly worn rotor or pad)

[icebiker]

Originally Posted by PhatLyfe

That's awesome, which dealer is this?

BMW of Bloomfield. Even though they are 30 mins away from me vs my local dealer, their prices are considerably better, they do the video walk around as a standard service, the service staff is super professional (ask for Ahron or Ahmed), some of the techs drive M's themselves, there is a massive window in the waiting lounge that looks out on the service bays in case you want to take a peek at the work, and there is always an M car or three in the service area. They are quite aware of the handful of issues that the F8x platform can have (e.g. TMIC) and do a thorough job when checking them out. Highly recommend.