Iv had this problem for a while now. On my 88 SAS with hysteer when i brake, not all the time but most the time the steering will pull to the left. I was thinking it was just because i had big heavy tires that caused it but its got to be more than that. Its not consistent. Sometimes it pulls to the right also. If im going down the street and i brake it pulls to the left i let off the brakes and over steer to the right then brake again it will still pull it back to the left. Kinda confusing but hopefully you will understand what im saying. If i was to let go of the steerign wheel it will just about completly turn the wheel by its self while braking.
My drag link is pretty flat and my caster angle is also pretty good. I have fj vented rotors and the ifs calipers on an 84 toy axle. I can post pictures of everything if it will help. I am running wagoneer 7leaf springs and i dont have spring clamps on them so the leafs are flared out pretty bad, not sure if that could cause it to move around.
Thanks
Nathan