Test for faulty proportioning valve:
Drive the vehicle and have an assistant
observe during the performance of this test.
With vehicle at curb weight, decelerate
vehicle from 46 to 40mph (72 to 69 kph)
on dry concrete mad and apply sufficient
pressure to lockup front brakes. If rear
brakes lock up before front brakes, then
the proportioning valve should be replaced.
Replace proportioning valve, refer to
Method for checking hydrobooster:
Depress brake pedal several times to
exhaust accumulator pedal. Depress
brake pedal and start engine. Brake
pedal should fall, then push back
against operators foot.
Replace hydro-booster, refer to (para 7-14).
Replace service brake pedal, refer to (para 7-16).
The steering tests will check for suspension
problems that will affect braking.