Load valve in rear brake line

[kipps]

SweetK30 mentioned that this is commonly bypassed. How does this thing work?

My theory is that it's a simple valve that restricts braking force when unloaded. When loaded, it opens the valve, allowing full braking force. If true, a simple removing of the valve will bias the brakes toward the rear, since removal is the same as fully loaded. If it's removed, it seems the proportioning valve should be swapped out for a truck that did not have one of these load valves. Correct or no?

Is this valve even a problem? Why remove it?

Here's another thread discussing the issue, and evidently GM issued a tech bulletin a few years later instructing on how to bypass the valve. Keith Seymore says the valve was intended for passing a specific government test, and wasn't really applicable to the general populace. I have a little hard time believing that.

How does this valve fail? External leak only, or does it ever mysteriously block the rear brake line either on or off?