Use 2 brake pressure gages to check the brake proportioning valves that are attached to the master cylinder on non-ABS braking systems. These valves limit the outlet pressure to the rear brakes after a predetermined master cylinder pressure has been reached. On vehicles equipped with ABS, the hydraulic modulator assembly controls the hydraulic pressure to both the rear wheel cylinders and the front calipers.
When checking the brake proportioning valves, be sure that the hydraulic line pressure is measured simultaneously and diagonally on the front and rear axles.
To measure the pressure, use the following steps:
Important: If the pressure exceeds 10,000 kPa (1450 psi), the pressure reading on the rear gage will not be accurate.
Notice: Refer to Fastener Notice in the Preface section.
Tighten
Tighten the bleeder valves to 6 N·m
(53 lb in).
Tighten
Tighten the bleeder valves to 6 N·m
(53 lb in).
Engine | Reference Number for Gradient and Switching Pressure on the Valve Housing | Input Pressure Read on the Manometer at the Front Axle in kPa (psi) | Output Pressure Read on the Manometer at the Rear Axle in kPa (psi) |
---|---|---|---|
1.2S | 0.3/30 | 500 (73) | 500 (73) |
1.4/1.5S | 4 500 (653) | 3 450+/- 200 (500+/-29) | |
1.4/1.6D | 10 000 (1,450) | 5 100+/-300 (740+/-44) |