Brake booster problem on 91 Hilux??

[Ironloki]

My brake pedal goes down half way before the brakes actually DO anything. But if I stomp the pedal, it becomes
ROCK solid, and wont stop, untill i go easier on the brakes. any info? what ta do? Thanx. AND... the rear brakes
like to lock up on me as well, even when i go easy on it.

[bigarms23]

are you running a prop valve and when was the last time you changed your brake fluid and blead your brakes?

[Ironloki]

ahh.. the prop valve is not hooked up, the lever that goes to the axle rotted out, so the back's are right to the wheel cylinders. i thought that had something to do with it.. And I bled my brakes out a couple months ago, when i put new front calipers on.. the fluid is clean as well.

[79coyotefrg]

sounds like the master is bad,  its not holding fluid on the front side of the master,letting it bypass but the rear brakes are getting full pressure
you need one of these---> http://www.marlincrawler.com/brake/master-cylinder/big-bore-brake-master-cylinder

[Ironloki]

hey thanks man.. that sounds about right with the pedal travel and all that.. I shall most likely invest in that..
Is the prop valve not being hooked up part of the problem too?