engine and drivetrain Survey of rear disc owners

[Guest Anonymous]

Hey guys -

I've got a rear disc kit on my car and I have to say it's just not working as well as I expected. Something is wrong somewhere and I just can't figure out what it is.

Here's my current setup:

-E12 vented brakes on Tii struts

-E12 Master Cylinder

-Brembo brake proportioning valve

-Aardvarc rear disc kit

-Braided lines

Pretty much the best brakes you can buy, supposedly. Something isn't working right though. Before you suggest it, the proportioning valve is open all the way (no reduction).

I've bled the brakes many times and I really think that I've got it right. Even had them done professionally. Still, the pedal feels a bit spongy and if I run the car on jackstands, I can't even stall the engine from idle without really standing on the pedal.

So my latest theory is that the 5 series master was a bad choice. Originally it seemed like the right idea - obviously it's balanced for the fronts since they are also E12, but the rear E12's are two-piston and the kit brakes are just single piston. So presumably the MC would be dialed lighter because of the increased advantage of two-piston calipers, or am I thinking backwards?

So my survey is: which MC are you using and how do you like it? I'm considering trying a tii unit.

BTW Dave Varco has been very good about trying to help with the problem but he isn't sure around the MC issue...

-Hamish

[Guest Anonymous]

with the way the calipers hang down its a bitch to get them completely bled. Im not really sure where yours sit, but mine are at the bottom of the trailing arm, and i have to take them off to bleed correctly. I am actually still using a stock 2002 MC, and it stops like there is no tomorrow. just Squats and STOPS. i have a 5 series unit, but havnt tried installing it yet. How bad are they? did you do the front brakes at the same time as the rears? i still vote for air somewhere..... Best of luck though!

-Reid

[Guest Anonymous]

(nt)

[Guest Anonymous]

I've got a simlar setup with the front brakes and the Aardvark

rear disc, although I have a tii master. I have a hunch your

problem is still air in the lines. Bleeding the rear discs can be

tricky, as the bleed valve in the rear caliper faces down in this

application, and can trap air in the caliper. I always undo

one of the caliper bolts and swing the caliper up so the bleed

valve is the highest point, and then bleed. By the way, I have

never found any of the permutations of powerbleeders (either

pushing or sucking) to be as effective as the good old human

foot-on-the-pedal for getting out airbubbles in the line. I think

power bleeders are good for flushing the brake system, but

not so great for bleeding out air.

Just my rambling,

Ian

'776 M2002