Brake master cylinder

[doski]

yea and if your suffering from to much rear braking you might as well fit a brake bias kit

[30psi]

Yours will be a 1", the >86 models are 15/16"

On the S12 the rear brakes arent good enough to be an issue, doubt you could lock them up to be honest

[doski]

yea only ever managed to lock them up when going down a hill, turned a small s bend and doing no more than 30mph there was a bus near the bottom of the hill pulling into a car park so i started to slow down when they locked on and ended up sliding sideway down with my front end nearly dragging on a wall, and while trying to correct ended up facing the other direction stopped..........

luckily i didnt do any damage and was nowhere near the bus lol