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 45 to 40 mph (72 to 69 kph)
on dry concrete road and apply sufficient
pressure to lock up front brakes.
brakes lock up before front brakes,
the proportioning valve should be replaced.
Replace proportioning valve (para. 7-10).
Method for checking hydra-booster:
Depress brake pedal several times to
exhaust accumulator pedal. Depress
brake pedal and start engine. Brake
pedal should fall, then push back
Replace service brake pedal (para. 7-9).
The steering tests will check for suspension
problems that will affect braking.