How to adjust front and rear braking pressure?

[autobonrun]

Is there a procedure for adjusting the braking pressure that is applied to front and rear brakes to ensure it is to spec? Or is the ratio fixed based on the design of the master cylinder, and the only way to be sure is to rebuild the MC?

I finished rebuilding the calipers and replacing brake lines.

[Eric Coffey]

Not farmiliar with all years, but pretty sure it is a non-adjustable system. However, I know that the later Carrera's have a factory rear brake proportioning valve that determines (lowers) the rear brake pressure. I have never heard of one going bad though.

[Kahuna]

check here, lots of info!!

Brake info

[Don Wohlfarth]

On a stock brake system it is fixed and I have never seen one fail.
If I were to guess on how to check the valve I would measure the brake pressure to the front and rear calipers and figure the ratio. If the bias valve is accessible just check the inlet/outlet pressures and find the ratio.
I've got adjustable dual m/c on my 914 and wondered exactly what the ration was since I kept adjusting until the rear locked up and then backed it off. I found exactly what I was looking for from Pegasus, a dash mounted bias instrument with a direct readout. The device was $785.00 and I decided I didn't want to know that badly.