Hombre XS Space Cab L4-2.2L CPC (1997)
Brake Proportioning/Combination Valve: Description and Operation
PRESSURE EQUALIZATION
The combination valve has three sections. Each section serves a different function.The metering or hold off section limits pressure to the front disc
brakes until a predetermined input pressure is reached. This should be enough pressure to overcome the rear brake shoe springs. There is no
restriction to inlet pressures below 200 kPa (30 psi). This allows for pressure equalization during the no apply periods.
AFTER A MALFUNCTION OCCURS
The pressure differential warning switch constantly compares front and rear brake pressures from the master cylinder. If the front or rear brake
systems malfunction, it energizes the warning lamp in the instrument cluster. The switch latches in the "warning" position after a malfunction
occurs. The only way to turn off the lamp is to repair the malfunction and apply enough pedal force to develop about 3100 kPa (450 psi) line
pressure.
FEATURES
The Proportioning Section - limits pressure to the rear brakes after a predetermined rear input pressure has been reached. This minimizes rear
wheel lock-up on vehicles with light rear wheel loads.
The Combination Valve - includes a "by-pass" feature. This ensures full system pressure to the rear brakes in the event of a front brake system
malfunction.
