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I have something going on with my brakes. The brakes are not fully releasing when I let off the pedal. The condition is intermittent, and based on some threads I've read here on Big Coupe, it sounds like a common problem with the MC.

I'm going to replace the MC. I still have the original e24 calipers, and I"m not looking to do a full brake upgrade at this point. Any recommendations on going with the stock e24 or going with the e32? Based on another thread, it looks like this is the correct e32 part: 34311156643

The cost is a bit lower on the e32 part. If it's a completely plug and play situation I might go with the e32 part since it would save me a few bucks and would get set up for a future caliper upgrade. Thoughts?

Fellow Members,

I also went with the e32 M/C with the larger bore, and saw/felt no difference.
Make sure you get the early e32, as there are two styles.
The e32 was also less money.

Best,

Swapped my master cylinder today. Definitely plug and play. I haven't really noticed much difference in terms of performance, but I've only driven it around the neighborhood so far. I'm glad I went with the e32 MC so I can do the full brake upgrade at some point.

I wasn't really planning to do the full brake upgrade, but since the master cylinder was done, I started thinking about it. Last weekend was 50% off at my local Pick-n-pull, and they had an e32 and e34. I went out there and the full brake system was still intact on both cars. So I got all the parts and installed everything this weekend.

I want to that everyone that documented the swap. I never would have been able to figure out which parts were compatible. I was truly plug and play. The rotors fit in the dust shields, everything fit perfectly.

I'm happy with the upgrade, really nice improvement in braking. If anyone local needs a set of barely used standard e24 rotors and pads let me know! I don't remember exactly when I replaced them, but I probably only have a couple thousand miles on them :).

I found this MC on amazon. Someone knows if these one will fit my 635 csi? Thanks.

https://www.amazon.com/URO-Parts-34-156 ... way&sr=8-1

tonomontt wrote: ↑Tue Jun 25, 2019 2:48 pm I found this MC on amazon. Someone knows if these one will fit my 635 csi? Thanks.

https://www.amazon.com/URO-Parts-34-156 ... way&sr=8-1

That part number shows as an E32 from 06/01/86 - 01/18/2019. Look at www.realoem.com for full application lists.

tonomontt wrote: ↑Tue Jun 25, 2019 2:48 pm I found this MC on amazon. Someone knows if these one will fit my 635 csi? Thanks.

https://www.amazon.com/URO-Parts-34-156 ... way&sr=8-1

Yes, that is the e32 MC that will work. I opted to go with the OEM ATE brand MC rather than the URO-Parts one, but that is the right part number.

One tip that I'd share, I accepted the fact that some brake fluid would spill during the job, and put a good supply of rags below the MC. Then I used my vacuum pump to suck the fluid out of the reservoir, then removed the reservoir. That allowed easy access to all the connections and made it easy to remove the MC.

When I put it back on, I installed the reservoir, did the "bench bleeding" outside of the car, then removed the reservoir (which potentially put air back in the system, but at lease the internals had fluid). It would be more difficult to install it with the reservoir on. I had no issues bleeding the full system after the installation.

Thanks very much dmac. I will do it as you say.