What else to replace when replacing Master Cylinder?

[Stu]

I will probably replace my MC this weekend, stock to V12 unit. I know I need two of the gaskets/grommets that go under the fluid reservoir, but are there any other parts needed?
Any help is appreciated from those that have done the procedure.

Thanks

[BimmerToad]

Make sure you use flared wrenches on the hard brake lines so that you don't run the risk of stripping the metal 'crush nut' things.

[RobertK]

Please excuse my ignorance but what is the "v12" unit master cylinder?

[James Crivellone]

Please excuse my ignorance but what is the "v12" unit master cylinder?

From a 750iL. 25mm as opposed to the E30's 23mm

[kowalski]

what exactly is the advantage to that?

[e30Matt]

what exactly is the advantage to that?

Better brake pedal, more of a "squeeze" feeling than a "stand on the pedal" feeling.

As for the master cylinder, use a flared wrench as mentioned above, and I assume you're doing a flush on the brake fluid.

[dableds]

Don`t forget to change brake fluid in all system :)
and wash the reservoir with new brake fluid

[SchnellerVert]

Stu, talk to UNHCLL, he did it and I believe he was not pleased with the setup.

[DanGillan]

yea there was a issues somewhere about the 25mm master "feeling" better but performing worse. i could be wrong. check it out though

[Stu]

Cool, so it looks like just the MC, gaskets and flushing the reservoir.

I'm replacing the master cylinder with the V12 unit because: a) my MC has 285k on it and I believe it is causing my mushy pedal. b) i have a brand new, in box V12 unit available for use at no cost. I'm using it with the stock calipers/rotors for a short while before upgrading this winter.
I'm not expecting a jump in braking performance, I just expect a solid pedal and an MC that will move a lot of fluid. Pedal feel is purely preference anyways, I may adjust the brake pedal if necessary.

[Mystikal]

From a 750iL. 25mm as opposed to the E30's 23mm

E30 M3 is 23mm. Ours are even smaller.

[nickmp0wer]

you might want to replace the o ring that goes in between the booster and the MC or at least remember to put it back in unlike me. I definatly noticed a decrease in performance when i forgot to put it back in, but i cant say anything about with it in becasue i changed the pads and rotors and shit. Write a review after you install yours

[nickmp0wer]

so how did it affect the braking performance?

[James Crivellone]

E30 M3 is 23mm. Ours are even smaller.

Really? the one that came with my car was listed as 23mm on the side and had the correct E30 325 part number

[Mystikal]

Really? the one that came with my car was listed as 23mm on the side and had the correct E30 325 part number

From what I recall the stock MC is like 19mm, hence why the 25mm model is such a drastic change (and why some believe it's not productive). If it was really just a 2mm change, people wouldn't be responding like that.