Are they the same?
 

I've tried searching but I'm not coming up with what I need. Are the R53 and R56 REAR brakes/calipers the same?

I just picked up a pair of R56S front brakes to upgrade my R53 with. I'm looking into rotors for both and from what I can tell/research the rear rotors are both the same mm size. Now, with that being said are the rear caliper brake line holes the same size? I know when changing out front brake lines the R53 and R56 are different sizes. Just because the rear calipers are the same rotor dimension I wasn't sure if the calipers had differing brake line hole sizes. I was just thinking about ordering a set of SS lines for the R56 if they would fit both. If so I think I'm good but if not I have to source a set of front and separate set of rear. Thanks for all the help!

I want to say no. Suggest you check the part numbers via RealOem

https://www.realoem.com/bmw/select.do

They aren't the same number, even on the updated part numbers for the closest year. Hmmm, now I guess I need to find a separate set of front and rear ss lines for each generation.

NO R53 and R56 rear calipers are NOT the same. The rotor diameter is the same though. Unless you go to the R56 JCW rear rotors and caliper brackets. They also use different shape pads.

If you have the later screw in style rear R53 brake lines they will screw into the R56 rear calipers if you convert.

If you are going to put R56 Calipers on the front do NOT order R56 brake lines. They are not correct to mount to the body. You need our specific R56 brake conversion lines that are designed to fit the R53 body end, but have a floating end to screw into the caliper and not get the line twisted up.
https://www.waymotorworks.com/stainl...rsion-kit.html

we offer the rear conversion too, but like I said if it's a late car you can use the R53 lines in the rear.