[ClaudioM]

Long story short, bolt disappeared causing whole bunch of ABS issues reason unknown. I was lucky nothing worse happened the ABS system did its job. 34106864424 is the part # RealOEM is telling the correct one is but my car has 18mm bolts currently in place. Do I need to switch over to the bolt stated on the website? If not what is the part number for the 18mm bolt I couldnt find it searching around.

[e91Owner]

Originally Posted by ClaudioM

Long story short, bolt disappeared causing whole bunch of ABS issues reason unknown. I was lucky nothing worse happened the ABS system did its job. 34106864424 is the part # RealOEM is telling the correct one is but my car has 18mm bolts currently in place. Do I need to switch over to the bolt stated on the website? If not what is the part number for the 18mm bolt I couldnt find it searching around.

18mm seems a little large unless you have an aftermarket brake kit. That's a bigger head than your drain plug. The standard part when e90s were produced was a 12mm hex bolt with a 16mm head. The new part that you mentioned is a 12mm etorx with an E16 head. If you want the original hex head it would be part number 34116772117. As long as the threads match, it wouldn't matter what the bolt head size is.

Personally, I would get the hex head as it is easier to apply wrench to them.

[Efthreeoh]

Okay, so you have some confusion going on. So just for edification, a bolt is measured by its thread size and not the size of the bolt head. This bolt is a 12MM (diameter) x 1.5 threads per millimeter (i.e. "thread pitch") x 43MM long. I checked realOEM. BMW switched the bolts from hex head to E-torx with the latest P/N change.

But you are being confusing because you titled the Thread as "caliper to carrier bolt", which is not correct. The caliper is located on the carrier by "guide pins", which are Allen-head pins, not bolts.

I'd get 4 ea. new new bracket bolts in the P/N you called out. If the bolt broke, it probably wasn't the correct grade of steel. Buying the genuine P/N bolt will get the correct grade of steel (i.e. bolt strength) back holding the carrier to the hub.