I have read a lot of stuff about this Load Sensing brake prop valve. It is a great idea if it works. Mine does not.

I have adjusted it all the way down, all the way up (tied it to the frame). Reworked an verified function of the rear brake mechanicals. The brakes are adjusted and will self-adjust. My e-brake works great but I get very very little rear braking. If I am lucky I can get the rear wheels to lock up on ice.

Normal driving is not so bad but towing my boat is not so good. What goes wrong with these things and how do I check/rebuild/clean it out so that it functions correctly.