Skylark V6-173 2.8L VIN W FI (1985)
Proportioner, rapid deceleration
Proportioner, normal braking
Proportioners installed in master cylinder
Proportioner Valves
During rapid deceleration, a portion of vehicle weight is transferred to the front wheels. This resultant loss of weight at rear wheels must be
compensated for to avoid early rear wheel skid. The proportioner or pressure control valve reduces rear brake system pressure, delaying rear wheel
skid. When the proportioner valve is incorporated in the combination valve assembly, pressure developed within the valve acts against the large
end of the piston, overcoming the spring pressure, moving the piston left. The piston then contacts the stem seat and restricts line pressure through
the valve.