Margal

I am going to upgrade my 545i brakes to OEM m5 brakes. Purchased the caliper used set. I noticed no deference in rear calipers comparing them to 545i. Fronts have two pistons and they sure are m5 but wandering about rears as they only have one piston and all the numbers are same in m5 and 545i calipers
Please someone tell me how I am going to make sure that I have m5 rear calipers? I can't see part number on them?
Thanks

545iMike

Put them on your car. M5 has larger rear rotors. If they sit out farther from your 545 rotors they are M5.

M5 RR- 34 21 2 283 164
545i RR - 34 21 6 753 680

What do you mean "all the numbers are same in m5 and 545i calipers."

Margal

What is RR rotor or caliper?
I can not see that number on the caliper. all I see is something 46/24. 83 7V on both calipers on different places

545iMike

Right Rear caliper.

Checked rockauto.com for calipers. Centric brand calipers list the same picture, dimensions, and part number for both M5 and 545. Also checked for used listings and found this one https://5series.net/forums/private-m...t-rear-118451/
Has the same numbers you had listed. I don't know how 1 caliper could possible fit both a 345mm and a 370mm rotor. You will have to remove one of the calipers and see if there is and side by side difference. Also mount the m5 rotor and see if either caliper fit.

ETNav382

As I am currently in the processing of whacking off(no jokes) my right rear rotor, I made the same discover about the calipers. The only difference between M5 and 545/550 rear rotors is the M5 ones are painted black. Also, if you check R1, the rear pads for M5 and 545/550 are the same numbers.

Margal, where did you get you brake set from?

Margal

I got it from the guy you referred. He was fast in shipping but not quite happy with set as the rotors look like they are from deferent cars as some have painted head and are in different thickness.
There is than no reason to replace the 545i rear calipers with M5 than, If there is no difference
Visually they look like same size and almost identical to me. Except as you mentioned M5 calipers are painted black

ETNav382

Ok, how are you the pads he sent you? The rear pads on my car had a good bit more material than the ones he sent. Considering my rears have been on for about 45k-50k miles, I'm wondering how many miles they actually have on them.

Margal

i would not put the pads on as they look not to much life remaining and they are not original BMW. there wore no sensors and lines as he stated in his listing. I am just painting calipers he send to me and hope that they will work.

ETNav382

Hey Margal, have you completed this mod yet? I did yesterday and have a ridiculously spongy pedal. I've bleed the system twice using the BavAuto bleeder. I'm thinking my master cylinder may need replacing now.

Margal

No, not yet, still painting and waiting parts to arrive. If you brake was good before than you probably have some air in my your system. I think you have to bleed it again with lot of brake fluid