Proportion/pressure/metering valve?

Perportion valve is not to be repaired or renewed. Reason being, A master cylinder will fire a few warning shots before it kills you. A perportion valve will not. It can dump all the brake fliud in a heatbeat. It can fail to supply fluid pressure to any line, firm pedal or not. Buy a new one. Master Brakes gets about 60 bucks for it.