Brake Master Cylinder size

Post Thu Feb 07, 2013 11:04 pm

Hello, can anyone advise on what size master cylinder would be best for the following setup. Just trying to decide between the standard e30 325i one, e30 m3, or an e32 750i one.

My brake setup is as follows. The Porsche boxster 2.7 which is what my brake calipers and disc sizes are from have a 23.8mm master cylinder.

This is my brake setup. I have a Renault clio servo so the assistance may be less than the e30 one. I also have a tilton bias valve in line with the rear calipers. Original bias valve is non existent.

Front 4 pot:

40mm
36mm

300x24 disc
216cm^2 pad area

Rear 4 pot:

30mm
28mm

294x19 disc
196^2 pad area

Tyres are 195/50/15 R888

Thanks in advance,
Harjun.

Post Thu Feb 07, 2013 11:42 pm

Just looked and it appears that the e30 m3 mc is 23.81 mm which is the same size as the Porsche boxster one. I guess a 25.4mm one should be fine. Not to keen on the servo assistance provided by the small clio servo though.

Post Fri Feb 08, 2013 9:14 am

If the Porsche brakes came with a MC the same size as the M3 then thats where you should be starting from, ive fitted clio servos to plenty of E30's in the past and always found they give better assistance than the standard servo

Post Fri Feb 08, 2013 11:56 am

Does the Porsche have the exact same MC size front and rear?

Post Fri Feb 08, 2013 12:15 pm

I'm not really sure. On the specifications for the Porsche master cylinder it just says 23.8mm. I don't know if that means it's the same size front and rear. Would it be possible to tell from a picture of the master cylinder?

Maybe the 25mm won't be too stiff after all, as that's what I'm fearing at the moment. With regards to rear bias, hopefully my proportioning valve will get that perfect.

Interesting about the Clio servo. I think my situation was strange when I tried the Clio servo, as I was using awful pads and discs so I don't think that would have helped. Does the servo offer quite a bit more assistance than the standard e30 one?

Thanks for the help

Post Mon Feb 11, 2013 4:10 pm

Porsche will likely have same size front /rear

Post Mon Feb 18, 2013 3:33 pm

After reading through the Ate catalogue, ended up getting an e32 750i one

Post Mon Feb 18, 2013 4:00 pm

Where'd you get it from? The best I can find is £143 from CarParts4Less.

Post Mon Feb 18, 2013 4:03 pm

Jimbob wrote:Where'd you get it from? The best I can find is £143 from CarParts4Less.

I didn't get a new one.