[Alan l.]

FYI my 2020 X5M with 30K miles on it is due for new rotors all around based in the minimum thickness requirements stamped on the rotor hats. This is with oem pads for most of its life(swapped to isweep just 3K miles ago) and ZERO track sessions. Just normal day to day NYC driving.

Something to keep in mind if your mileage is similar. I got this gauge on amazon to tell me where i'm at now and measured it when i was swapping over to my winter wheels.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1


4 new oem rotors with new set screws will run you about $1360 from getbmwparts.com

Alan

[eelnoraa]

$1360 for 4 rotor on a M car isn’t bad at all, right?

When you swap pad, did the wear sensor trip? How was the pads that you swapped out? Are they close to be done?

Brake wear has a lot to do with driving style. The same exact cars, i have seen front brakes last 20k on one driver, and 90k on another where wear sensors weren’t even tripped.

[starlights]

How does one determine the approx rotor/pad wear from within the car? I did not see it in the iDrive under vehicle status like previously on F10...

[eelnoraa]

Originally Posted by starlights

How does one determine the approx rotor/pad wear from within the car? I did not see it in the iDrive under vehicle status like previously on F10...

He must have measure the rotor thickness using a low profile caliper type of tools.

Idrive only tell you brake is ok or need replacement, 0 or 1. It basically read the brake wear sensor embedded in the middle of the brake pad. If sensor makes contact with the rotor, rotor will grind through the sensor and crest open circuit. Idrive tske that as your brake need replacement. Idrive does not know rotor thickness.

[Alan l.]

Originally Posted by eelnoraa

$1360 for 4 rotor on a M car isn’t bad at all, right?

When you swap pad, did the wear sensor trip? How was the pads that you swapped out? Are they close to be done?

Brake wear has a lot to do with driving style. The same exact cars, i have seen front brakes last 20k on one driver, and 90k on another where wear sensors weren’t even tripped.

Price isn't bad considering what you are getting. I'm saving a boat load by doing the install myself and ordering the parts at a discount. Figure the parts for rotors, sensors, pads would run well over 2K if you bought it directly from the dealer parts dept. with their mark up plus labor for the install you are probably paying 4K for a full brake job there.

When I swapped pads the stock ones still had plenty of meat on them and did not trip the sensors. Wish i measured the rotors then saving me from doing the same exact procedure twice but its not hard to do.

Alan

[Alan l.]

Just changed all 4 rotors myself. Here are some pointers for those DIYer...

Its easy to do but both the fronts and the rears gave me separate issues. Steps are 95% same as changing pads.

Issues:

Front - There are two screws holding the rotor to the hub. Mine were seized on and would not come loose without stripping the 5mm hex head. My recommendation is to have those two new ones ready in case you strip yours and need new ones. They were about $2 each. What i would have done differently if i did it over again was take a hammer and pound on the rotor hat all around a dozen times to loosen the corrosion. You have to do this step anyways for the rotor to come off. It could have helped me loosen that rotor screw before hitting it with a impact gun in hind site. Since both of mine were stripped i didn't end up using them at all which is fine. The M hubs have 3 protruding tabs that helps seat the rotor and prevents it from spinning and the lugs holds the rotor in place.

Rears - you actually have to remove calipers where as doing the pads you are just swinging part of the caliper up. The two bolts holding it in place is behind the hub and its pretty tight in there. I had a tough time getting enough leverage to loosen the bolts. that took me the longest. My impact gun was just a tad too big to fit back there so i had to muscle it the old fashion way. Having a smaller heavy duty impact gun would have saved me alot of time here. No issues with the rotor screws in the rear because bmw used a different style screw in the rear that doesn't strip as easily.

Also have a wire brush attachment to clean off any rust on your hubs before installing the new rotor. I got one that attaches to my drill to do it much faster.

Alan

[eelnoraa]

For taking out the screw holding the rotor to the hub, there a tool specific for that. It is like a screw driver with spring loaded shaft. If I hit the handle with hammer, the shift retract and at the same time turn counterclockwise. It is making sure pressure is applied in the screw head, impact to loosen the screw. Very inexpensive tool, worth a while to get one.

[Alan l.]

link please.

My buddy was just telling me about a tool like this which i've never heard of. That screw literally doubled if not tripled my install time for the front rotors. I could probably do each rotor in 15mins if not for the stuck screw.

Alan

[eelnoraa]

Originally Posted by Alan l.

link please.

My buddy was just telling me about a tool like this which i've never heard of. That screw literally doubled if not tripled my install time for the front rotors. I could probably do each rotor in 15mins if not for the stuck screw.

Alan

Something like this: https://www.amazon.com/DURATECH-Reve...zcF9hdGY&psc=1

Mine is 20+ years old, doesn't look as fancy as this.

[pixelate]

If that set screw is similar to ones on my Boxster, my advice when installing it is:
a) don't tighten it very much -- finger tight only?
b) put a tiny amount (just a very thin film) of anti-seize paste on the threads and/or collar so it won't stick to the disc or hub. (depends on the shape and where contact is being made that can corrode and stick)

Why? The screw is ONLY used to hold the brake disc steady in place before the lug bolts are put in place and tightened. The 5 lug bolts hold everything in place for real with tons of torque. The set screw is doing nothing at that point; you just need it so the disc doesn't wobble around during assembly prior to fitting the wheel & bolts in place. No reason to tighten it down beyond that. For this very screw and its issues, I have a manual impact driver that looks virtually identical to the one eelnoraa posted, but since taking the "light touch" approach I don't think I've needed to use it, and I've replaced quite a few brake discs on the race car over the years.

(Someone please correct me if the X5 set screw is for something else!)

[Alan l.]

Thanks for the info. I might get this tool just to have in my setup for future projects. Too late now. both sets crews for the front rotors are drilled out and the threads are shot so i'm not running any up front. Its perfectly fine to not run them its just more of a convenience thing when the wheel is off and the rotor can shift slightly. It cant fall off since the caliper is still holding it there. More so the hubs on the M have 3 protruding prongs that aligns the rotor to the hub so even without the set screws the rotors can't not spin.

If bmw just used the same set screw they did in the rear for the front it wouldn't be an issue. Its a 6mm hex vs 5mm hex and those came off easily. Even after i drilled off the head of the 5mm screw it still didn't want to budge and back out like it was seized.

Alan