How does a proportioning valve work?
A proportioning valve is a valve that relies on the statics to supply a reduced pressure to an output line.
A simple example is where spring load applies a reducing force so that the output pressure is reduced.
Proportioning valves are frequently used in cars to reduce the brake fluid pressure to the rear brakes.
How do you check proportioning valve?
Test Combination/Proportioning Valve Use a test light by attaching a clip to a positive contact on the vehicle and touch the point of the tester to the electrical connection of the combination valve. If the the light does not come on, the valve system is operating correctly and no further testing is required.
How do you reset a proportioning valve?
To reset the proportioning valve try bleeding the master by applying pressure and slowly opening one line at the master until the valve centres. you may have to do the same with the other line to get it to centre, sometimes you have to hit the area where the valve is as it may be stuck to get it to move.
Part # PV4, Side Bracket, + 1/2" and 9/16" Lines.
Comes with compatible disc/disc proportioning valve kit
(self adjusting valve, pre-bent lines for 1/2" and 9/16" master cylinder ports, bracket to mount kit to the side of the master cylinder, and bolts)
The proportioning / combination valve performs all of the necessary valving functions with a disc brake conversion…
Proportioning:
As more force is applied to the brakes the car will begins to lean forward,
less braking force is needed in the rear.
This valve decreases the pressure to the rear which prevents them from locking up.
Applications include but not limited to:
- 1964-1972 Chevrolet Chevelle
- 1964-1972 Chevrolet El Camino
- 1964-1972 Pontiac LeMans
- 1964-1972 Pontiac GTO
- 1964-1970 Pontiac Tempest
- 1964-1972 Oldsmobile Cutlass
- 1964-1972 Olds 442
- 1964-1972 Buick Skylark
- 1970-1972 Chevrolet Monte Carlo
- 1968-1974 Chevrolet Nova
- 1971-1974 Pontiac Ventura
- 1967-1969 Chevrolet Camaro
- 1967-1969 Pontiac Firebird
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1.Use a test light by attaching a clip to a positive contact on the vehicle
and touch the point of the tester to the electrical connection of the combination valve.
If the light does not come on, the valve system is operation correctly and no further testing is required.
2. If the light does come on, this indicates that the pressure differential valve is stuck in the front or rear position.
3. Bleed the brake system to determine if the front or rear lines are blocked off.
Set up one front wheel and one rear wheel for bleeding at the same time.
Crack both bleeder screws and gently pump the pedal a few times. The blocked
side will trickle fluid out when the bleeder screw is cracked and the pedal pressed.
An unblocked line will squirt fluid out the bleeder.
4. The lines that are clear must be left open
and the blocked lines should have the bleeder screws tight to cause pressure to build up on that side.
Be sure to use the standard bleeding procedures to prevent air from entering the system.
5. Slowly press the pedal with steady pressure a number of times until the light goes out;
this will center the differential valve. You may also hear a pop come from the proportioning valve.
This is the metering valve returning to its equalized position.
When the light goes out, close the bleeder screw.
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