Fleetwood FWD V8-252 4.1L (1986)
Brake Proportioning/Combination Valve: Description and Operation
Valve Block Operation, ABS
The ABS uses the valve block to individually control the hydraulic pressures in the LF, RF, and rear channels during antilock braking. During antilock
control, the EBCM will respond as follows
^
Complete the main valve solenoid circuit
^
Control hydraulic pressure in any of the three channels by operating its inlet and outlet valve in this sequence:
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Pressure maintain - Complete the inlet valve circuit, blocking the wheel cylinder from booster pressure.
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Pressure decrease - While the inlet valve is blocking, complete the outlet valve circuit. This drops the wheel cylinder pressure, as fluid flows to
the reservoir through a master cylinder passage.
-
Pressure increase - Open the inlet and outlet valve circuits, allowing booster fluid under pressure to re-apply the brake. A driver feels the effect
of valve block operation during antilock braking when the brake pedal pulsates after it rises against foot pressure. The driver may also hear
clicking noises as the pedal moves, especially if booster pressure is high.
