E30 M3 Brake Master Cylinder Options

[danderson]

I have an 1986 325i with M3 suspension and brakes but no ABS. I did the swap last spring and used a stock non-ABS E30 master cylinder with the setup and I wasn't happy with the pedal travel and feel. With the smaller 21mm master cylinder I assumed I wasn't moving enough fluid for the calipers.

I had a spare E9 master cylinder, same diameter as the M3, lying around and figured I would try that. All of the brake lines fit into the master, it bolted to the booster, and it was larger diameter than stock. I bled the brakes and drove it for a few days. The pedal felt just as terrible as before and now the rear brakes weren't working until I was really pressing on the pedal.

So now I'm back to square one. Are there any other options for larger, non-abs, master cylinders for an E30? I'd like to avoid buying an M3 or one of the 25mm 750il master cylinders and having to run all new lines but if that's my only option for a solid pedal...

Any advice would be greatly appreciated.

[Bmjpv]

m3 brakes

I also have e30 m3 on my 88' Is with ABS (standard) and master from a 750. My point is to get a softer pedal,which will give you higher line pressure ,I think you need to go smaller dia master and not larger like you wrote. Just my thoughts, Joe

[benyen soljax]

Solid feel has more to do with the condition of the brake lines and how well you bled the system, also whether there are any leaks.

The stock rubber brake lines wear out over time and will feel less solid as time goes on.