Fitting E34 Brakes

If you've dramatically increased your engine's power, either by an engine swap or Forced Induction, then you're going to need some bigger Brakes.

This guide walks you through fitting E34 calipers together with an E32 servo and master cylinder. The standard E30 master cylinder is not big enough for the E34 calipers.

Parts

Front and rear calipers from an E34 Caliper adapter brackets Audi 312mm discs

Tools

Die

Procedure

After a lot of messing about with grinders, burrs and drilling discs to fit, I decided to go with something tried and tested BMW E34 540i calipers front and rear Scored the front brackets first all the way from germany

E34Brakes001

These were designed to be used with the above caliper and an audi 312mm disc Picture from google to compare the calipers E34Brakes002 (download new version)

Difference between stock e30 disc and audi one E34Brakes003

Because I've put the E34 calipers on the front and plan to do the rear the standard E30 master cylinder isn't big enough to move enough fluid everyone just uses the E32 750i MC but I also wanted more assistance to match, also the cost of these MC's are silly now so I saw a thread on an American site that used an E32 735i MC and servo, its still a 25mm MC so should improve the feeling to near stock level

But one problem is that a few mods are needed, the E32 I got mine from had a spacer on the back of the servo. There are two options here 1. use the spacer requires the least mods but the brake fluid resiviour will be right underneath the inlet boot on the m20 and possible fouling 2. Ditch the spacer but then a few mods are needed, these are: Grind down and shorten the push rod to put the clevis at original level Open up 2 holes in the bulkhead Bend the brake lines slightly

I choose number 2 for an original look to the engine bay

opened up holes E34Brakes005

ground down the pushrod E34Brakes006

started to make the thread E34Brakes007

About an Inch and half cut off, also threaded as far as I dared E34Brakes008

remember if your doing this then leave the die wound on before you cut it off so you can then unwind it and clean the threads so the clevis will go on with no trouble

test fit E34Brakes009

I was made up that the standard E32 vacuum line was in the perfect place to line up to the E30 system Smile

the clevis was the tricky part I lost the E30 clevis so I used the E32 one but it was way too long so needed trimming and slight mods so please keep your e30 one unless you want some trial and error fitment issues that involves installing ad removing the servo/clevis multiple times E34Brakes010

All done apart from take it all apart to paint the servo and bench bleed the MC E34Brakes011