proportioning valve on my coupe
 

A little help if you would. I have a Wildwood proportioning valve on my brake system and it appears to have a small leak where the knob goes into the body of the valve at the threads. There's no drip just a droplet on the knob head. I normally have to pump up the brake so its loosing pressure after it sits for a while. I have corvette dual master cylinder with no booster under the floor. I installed the two residual valves [2 and 10lbs] 2 lb for the front brakes and A 10 for the rear, and the proportioning valve sits behind the 10lb residual valve. My question is why does my pedal go practically to the floor if just the rear system is leaking a little air? are not the two systems independent of each other? I can't find any other leaks and everything seems dry. Are the Wildwood valves repairable? Do I want less pressure or more pressure at the rear? Where would the knob normally be set at 1/4, 1/2, 3/4 out? any help would be appreciated. Bill

my thought is the residual pressure is getting lost in the rear system because of the leaky prop valve, causing the low pedal.
I would get a replacement prop valve, as the one you have probably has a defect that may not be repairable.
If you plumbed the prop valve in the line Before the residual valve it may fix the problem (except the leak) as the pressure will hold on the residual valve then.

Latech, thanks for the reply, My brake system is freshly made except for the prop valve which I had used on my 54 pick up until I had gone to the CCP booster and cylinder on the firewall. All of the underfloor diagrams I've seen show the prop valve behind the residual so I'll buy a new prop valve and go from there. Thanks for the help. Bill

I have the same problem with my prop V. Let me know how u make out.

I had a prop valve that leaked just like yours. I never found any way to repair it. I ended up replacing the unit. Problem solved !!

I always mark the unit and the knob at the closed (left) and open (right) position . I then mark at the adjusted position. It helps me remember in case I ever need to change the adjustment.

Right or wrong, I count the number of turns from the closed position (left) to the open position (right). Turn the knob slowly and softly.

I then turn to the closed (left) position and turn to the right 60%. That has always been a good starting point for me. Not all cars will be the same, so adjust it as you need to and good luck.

I would like to hear any other comments about this. Bring them on guys !!

I hope this helps.

454 RATTLER

Yesterday when I posted this I was sure that the open and closed positions were correct. Not I'm not too sure. Be sure to check your valve for which is open and closed. Then adjust to 60% and start from there.

I am sorry if I screwed you up.


454 RATTLER

You are correct: CCW (left) DECREASES the available pressure; CW (right) INCREASES it. So far I haven't seen a valve that was the other way around, but the knob should be clearly marked.

Sure glad to hear that I was right. I was about to crawl under a rock because I posted without checking.


454 RATTLER

portioning valve
 

I know on an OEM the main rod in the portioning valve needs to be centered to modulate front and rear pressures, but the leak guess I was fortunate.