I have a brake problem. The brake system has a leak at the combination proportion valve. My mechanic said that it needs to be replaced but he could not find the part. I looked also and no parts supplier that I know of indicates an after market part. I found a Youtube video of someone who had the problem 5 yrs ago and stated he finally replaced it with a GM part but did not state the part number. He has since died. He indicated the key was finding one with the correct fitting sizes. At this point I can not find a mechanic who wants to figure it out. If I could have someone figure out the part number I would order it and then surely find someone who would change it. Do you have a good enough repair manual that describes the fittings? I physically can not do the work myself.
Have you considered trying a junkyard? Also a proportioning valve usually leaks at the fitting not at the valve itself. It's really just a cast manifold. If its leaking at the fitting it's the brake line/fitting not the proportioning valve.
