After having difficulty getting the brakes in my panel truck to bleed, we discovered the old OEM proportioning (combination) valve was rusty and corroded inside. I replaced it with a new brass one from a local supplier, which remedied the bleeding problem, and the brakes work fine. The problem now is I have fluid weeping from around the reset pin on the front of the valve. A search on the internet would suggest that this is quite a common problem. I'm using DOT 5, so I'm not worried about paint. It's more of an annoyance than anything else. There's a small rubber cap that goes over the fitting housing the pin. I'm wondering if I clean off the fluid residue, put a small dab of urethane or silicon in the cap, stick it back on and let it cure, it may stop the leak. Has anyone tried this? Or is this a bad idea and I should replace the entire assembly? If I can solve the problem and avoid having to re-bleed the system, that would be great. But I don't want to be putting a Band Aid on a bigger problem. Suggestions?
This happened to me years ago. It was a CPP proportioning valve, and because they are not too far from where i live, I took the P-valve off my car and took it by their warehouse/store and they removed the front metering valve and put a new one in. The leaking stopped. (it had nothing to do with the rubber boot, it was the valve.) He told me I didn't need to remove the entire P-valve to fix it ...which implied I could have brought the car to them, had the metering valve replaced while on the car, and not worry about re-bleeding the system.
If your supplier isn't close by, maybe the vendor will send you a new metering valve and you can replace it yourself.....looks like a pretty simple task.
One of my friends drove his newly (2 yr old) restored Nomad to Omaha from TN and before he arrived there, the combination valve failed on his car... He spent Sunday and part of Monday going thru all that. Apparently CPP's combination valves are also poorly designed/fabricated...
Calling a combination valve a proportioning valve is a misnomer; the proportioning action inside the combination valve is only one of it's functions as they include a safety switch if a cylinder fails, and hold off function, (metering valve), as well as the proportioning function. I've never heard of a true 'proportioning valve' failing by leaking...
'55, '56, '57 Nomads North Alabama area Gary
Last edited by BamaNomad; 07-23-2019 at 10:39 PM..
It's the metering valve. There is a couple of rubber seals in the assembly that split and start leaking. You will not seal it up with anything smeared on, it is under pressure when you step on the peddle.
Here is the link: http://www.classicperform.com/Store/...ucks/PV-MV.htm
Call CPP and verify this will work with your prop valve. They have them and they are only 10 bucks or so. I ordered two when mine went out.
I replaced the valve, topped off the fluid and had the brakes back good as new after a half mile or so.
Last edited by astroracer; 07-23-2019 at 10:31 PM..
Thanks for the input guys. Ace57 & astroracer, that's exactly the information I was looking for...a relatively simple solution without tearing it all apart!! The supplier is really good at backing their products. I'll see if that's a part that they carry. Once I have one I'll swap it in before we hit the road to Bowling Green.
Location: Edmonton, Alberta, Canada in the Summer & Mesa, Arizona part time in the winter
Wilwood Adjustable Proportional valve.. Compensate for staggered tire sizes and Brake / caliper upgrades. I've had ones in cars over 20yrs ..never fail or leak.
Mopac Performance should stock it in Langley.. $45 CAD.