No worries Jose, my understanding is that the proportioning valve at the back controls the differential. The system should have equalised pressure to all from after the master cylinder and the proportioning valve allows the user to increase the pressure applied to the back brakes. I still think your problem is at the back?? I certainly am not a brake specialist though and hope you get another response if that does not sort it. When you did the disk brake swap did you readjust the proportioning valve or leave it set as per the drum brake setting?

I would have thought you'd see a reasonable improvement going drum to disk?


Good luck mate.