Today I removed the front calipers on my R60 Countryman so that I can paint them. Unfortunately one of the bolts that mounts the caliper to the caliper carrier broke. It's M8 22mm 10.9 grade. I got lucky and was able to remove the stub with a little effort. With the holiday weekend, and shipping time, it will be more than a week before I can get a genuine replacement from ECS. Locally, I can find M8 10.9 bolts in 20mm and 25mm lengths. Does anyone have experience (or opinions) on using slightly longer or shorter bolts in this application? Advice appreciated.

 

Was it item #3 in this diagram?
https://www.realoem.com/bmw/enUS/sho...diagId=34_1523

If so, that’s one of the slider bolts, and is very special. You could replace it with a regular bolt, but the caliper will not move as designed, and could cause your brakes to drag. This could lead to further problems.

I would chalk this up to an expensive learning experience, and just wait for the new bolt to arrive from ECS.

 

Thanks for the reply. It was #3 but just the M8 bolt that goes into the slider. The slider part seems fine and the M8 bolt seems like a standard 10.9 grade hex head bolt. Quite a bit of the broken stud was exposed so I was able to remove it without too much trouble. At the moment, I don't see why replacing the bolt part would be a problem. I'm not saying you're wrong, just want to understand before proceeding.

Here's a photo of what broke -- this is one of the others, not the broken one.

 

Check Ace Hardware. They have an amazing inventory of screws, bolts, washers, etc. - even chrome ones. I use them all the time for hard to find fasteners.

 

Thanks. I checked Ace. They have 20mm and 25mm but not 22mm.

 

As a mechanical engineer, making sure that you use the same grade bolt is the key. Try to make the same length, but longer here just means threads going into the slider more, shouldn’t interfere. I personally would use Lowe’s, find the matching grade bolt(Head should have markings to determine) and use a similar thread locking compound when re-installing. You can also order an oem bolt to replace during next opportunity, if you have any concerns.

 

I agree on using the same grade - I never substitute different grade. I measured the "recess" in the slider. It's 12.19mm. The connecting point on the caliper is 13.4mm. So the 25mm bolt will not bottom out. I'll use that for now and order an OEM replacement the next time I order from ECS. And I'll use Loctite Blue as specified.