astock165

As I look at my C4 slumbering away the winter up on jackstands I was looking at the brakes. Last winter I upgraded to the J55 13" fronts and left the stock 1 piston rears.

Since the stock 12" 2 piston fronts are now mothballed, would there be any major issues with mounting them on the rear?

Since they are designed for a 12" rotor they should fit.
Fabricating a suitable bracket is a given.
No parking brake shouldn't be an issue since I want to make a dedicated a/x & track car anyway.
I already have the DRM bias spring in the m/c (for the J55 upgrade).
One other advantage would be that it would now use the same pads on all four corners.

Thoughts? Ideas? Criticisms?

John Shiels

piston volume and bias may be a problem.

astock165

Is bias tied to piston volume or are they seperate issues?

BrianCunningham

There's a biasing valve in the master cylinder. You changed that out when you upgraded to the J55's right?

leadfoot2

Great question. I intend to do the same thing so will be interested in what people have to say. The only issue I see is getting the brake bias set correctly which will take some cut and trying.

Race Prepared

You could always install a proportion valve, make adjustments as conditions require at the track - during runs! See valve behind steering wheel in pic.

astock165

Yes, I upgraded to the DRM bias spring in the m/c when I did the J55s.