Brake Proportioning/Combination Valve: Testing and Inspection

Proportioning valve function test
1. Remove the front brake tube (B) and rear brake tube (C) from the master cylinder (A).
2. Connect two pressure gauges (D); one to the output valve of the front (B) and rear (C) brake.





NOTE: Be sure to bleed the system after connecting the pressure gauges.

3. With the brake applied, measure the front pressure and the rear pressure.
If the measured pressures are within the specified range as illustrated, the proportioning valve is good.





4. Reconnect the brake lines in their original positions and bleed the system.

NOTE: This table shows characteristics of the proportioning valve as the pressure increases.