Thread: Proportioning Valve? Dual inlet/outlet vs Single inlet/outlet

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Dago, if I were you...Id go with one p-valve on the rears with no residuals. That's the route I am going to do on my car. Maybe someone else will chime in and tell us we are on track or clueless...

Do you mean to run a 4 line or a 5 line combination valve?

A combination valve is both a proportioning valve and a metering valve or "hold off valve" together.

The proportioning valve is used in the rear to decrease the rate of pressure rise to the drums relative to the pedal force as weight is shifted to the front during braking. This prevents the rear from locking up under hard braking conditions.

The metering or hold off valve is used in the brake system to better balance the front to rear brakes. The valve does not allow the pressure to rise at the front disc brakes until the pressure at the rear drums has risen sufficiently to overcome the brake shoe springs. At this point the valve opens to allow full pressure to build at the front brakes.

A 4 line has a front line in, and a line out to a "T" to both front brakes & a line in for the rear and a line out to a "T" for both rear brakes.

A 5 line has a line in for the front and two lines out for the front brakes, one to each brake to balance them out side to side better, a line in for the rear and a line out to a "T" for the rear brakes.

When ever possible never run a Residual valve, unless your MC is lower than any wheel cyl or caliper. It will hold unwanted pressure against your brakes and cause extra brake wear.

Pat