Checking Brake Proportioning Valve for Chevrolet Vivant 2004

1. Check the fluid level.
2. If the fluid level is below MAX, refill the fluid to MAX.

Use two brake pressure gages to check the brake proportioning valves that are attached to the front underbody on non-ABS braking systems. These valves limit the outlet pressure to the rear brakes after a predetermined master cylinder pressure has been reached.

When checking the brake proportioning valves, be sure that the hydraulic line pressure is measured simultaneously and diagonally on the front and the rear axle.

To measure the pressure, use the following steps:

Remove the bleeder valve and install a pressure gage to one of the rear brake cylinders.

1. Remove the bleeder valve and install a pressure gage to one of the rear brake cylinders.
2. Install another bleeder valve and install another pressure gage to the diagonally opposite front brake.
3. Build pressure by pressing firmly on the brake pedal several times. The pressure indicated on the gage is not regulated and represents the actual brake system hydraulic pressure.
4. Build pressure until the test values are achieved.

Refer to Specifications table.

Important: If the pressure exceeds 10,000 kPa (1,450 psi, the pressure reading on the rear gage will not be accurate.

5. Remove the gage from the tested brake circuit and repeat the test on the remaining circuit.