Problems with proportioning valve on 89 4x4 22re

I have some info about the LSPV-BV on my web page:

-- Roger

No...bought it new...and nothing done to it. I thought about playing with the sensing arm, but it occurred to me that it would probably be more appropriate to adjust the actual LSPV instead of the arm (What happens when I really put a load on it). But I still have to figure out if "faking" it out with the sensing arm even fixes the problem. For all I know the valve is just shot. But, not knowing anything about how it works...thanks for the response...

Keep in mind that I'm not talking about insufficent rear braking...I'm talking about NO rear braking.

You adjust the LSPV with the sensing arm. Moving it higher makes it "think" there is more weight in the bed and thus it puts more braking pressure to the rear drums. You should make sure the drums are adjusted out properly. If the self-adjusting star-wheel is stuck, they won't self-adjust each time the parking brake is applied and then you won't have good rear brakes.

-- Roger

I'll try that then...Since the sensing arm has a finite range of motion, and there appear to be some adjustment screws on on the LPSV so I assumed that is where it would be adjusted.

As to the adjustment of the drums, I don't think that's an issue...yet. I'm not getting any fluid past the LPSV.

Thanks again...

The LSPV setup is very tricky, the manual doesn't recommend playing with it. Mine is 20 years old and never failed but maybe yours did ? No rear brakes ? check the naster cyclinder, the rear piston seals could be gone and leaking badly, so you get no rear pressure. I would doubt it's the LSPV.. If you have done the brakes recently then you need to adjust the star-wheel in the drums to take up most of the slack in the mechanism, then let the star-wheel do the self adjusting, it does this when you put on the brakes while moving in reverse, and when you pull on the parking brake. If you have 'brakes' when you pull on the parking brake then the problem is hydraulic pressure , not the rear mechanisms. Go to the master cylinder and overhaul that first , it's cheaper, easier and likely the problem. Leave the LSPV alone until there is no other possibility..