The brake pressure proportioning valve wore out after 20+years on my 51 ford. My mechanic replaced it with a new one from ECI, and in between a break in the atmospheric river storm, today, I picked it up. All is apparently well again. The valve was burning up my back brakes during a recent 500 mile trip. I was able to keep going by jacking up the rear end and releasing a bit of brake fluid from a cylinder whenever the drums started smoking. Not a good way to travel, but it worked as a temporary fix.