The Stovebolt Site Forums The Shop Area Driveline Brake lock up and proportioning valves

This is MacX's dad Keith making this post... And I'm a novice to these old trucks, so please bear with me... So far I have less than 1 hour of cumulative drive time in the 53 that Mac and I have just got running this summer... And the brakes work great so far, but we put a lot of hours since October making the brakes work, keeping as many of the original parts in place as we could along the way.

I'm confused about a couple of things in this thread, though.

John, is the MC for the power brake conversion mounted on the firewall, or still in the original location under the cab? Isnt the height of the MC relative to the wheel cylinders going to have some bearing on the residual pressure (gravitational) in the brake lines? I guess I should look up the part number you listed and make sure, but I assume its a dual chamber MC so it has 2 outputs, and each one splits evenly to the 2 wheels it serves?

Here's the part that really is bugging me, though. You say you only have trouble with 1 wheel locking up in the rear, and not 2?

If it was both wheels, evenly, then I would be satified that the issue is a balance between the correct residual valve pressure and even distribution valve/blocks, and driver management to regulate just the right pressure...(50's trucks are new to me, but I cut my teeth on 60's muscle cars when I was in my teens, so not locking up was a skill, but getting even brake pressure on the left and the right, was a critical mechanical issue ...)

So, in my experience, 1 out of 2 wheels locking up in the back is a sign of trouble somewhere... brake shoes that have different surface conditions (greasy, or sticky, or thinner/thicker left vs right...), or leaking wheel cylinder, or obstruction in the brake line.... something is wrong if you're not locking up both rear wheel evenly, isnt it? Whatever this fault is, if it was occuring on the front, it would be dangerous, because the truck would pull sharply to the side with the harder braking, and then emergency stops are extremely dangerous to manage...