Im interested on some advice with this setup - hilux 4 pot (s12+8 caliper) and U12 pintara discs. (R31 Rear)

I have done this in my CA Coupe and under hard braking it locks the front right and under firm braking it pulls left.

Im using a 180B master and booster, I removed the 180B poportining valve assy that I had when I had stanza drum brakes rear and stanza disc front. I replaced the poportioning valve for one off of a Ford Laser and I belive this to be causing the problem.

I ran the s12 calipers with the stanza drum rear end and the 180B poportioning valve and the car pulled up straight, but you locked the rears under hard braking.

I curious to know how you guys have the master configured? I spoke to Maddat and they said they dont use a poportioning valve. Just straight from the master into a y splitter and then to the brakes.

Any thoughts?

And sorry for getting off track in your thread