OEM Rear Brakes 1989 Comanche

[Dal3]

I'm finally trying to straighten out the my rear brakes. I watched a YouTube video by someone saying the OEM load sensing brakes do not work well and should be eliminated. I'd considered bypassing the proportioning system. However,  I am concerned the brakes on the wheels could be inherently more sensitive on this load sensing system. I have everything connected, but haven't bled the system. Is anything different bleeding the proportioning system?

Is there a diagram of the connections in this system I can use to confirm connections are correct? I haven't found these issues discussed in the forums.

[fiatslug87]

In order to bleed MJ brakes:

Open the right front bleeder

Depress brake pedal and hold

Start engine, brake light should stay on after engine starts indicating bypass valve has moved (sensed front brake leak)

Turn off engine, leave bleeder open, release parking brake

Bleed left rear 

Bleed right rear

Bleed righ front (close bleeder when done)

Bleed left front

then repeat bleeding with right caliper closed

 

from the ‘92 service manual

[Dal3]

Thanks for the reply. I'm trying to get information about the function, testing and servicing of the LSPV automatically variable rear brake proportioning valve.

I made a pressure bleeder adapter and applied 10 psi pressure at the master cylinder reservoir. I cracked open the supply fitting on the side of the LSPV and got a stronger flow of fluid there than from gravity alone, as I expected. I retightened that fitting then loosend the fitting on the top of the LSPV. The line from there connects to a Tee fitting joining it with the rear axle brake hose and another line returning to the vicinty of the master cylinder. I have guessed this is the way the variable braking is affected, by "bleeding off" part of the pressure as determined by the LSPV. I don't understand this system. And leading to this attempt to bleed the rear brakes, it was necessary to replace all of the lines under I've described. I think I correctly copied all the connections and the existing system in place looked OEM. I had the lever on the LSPV at 3:00 p.m. (viewing forward) and tried slowly rotating the valve, but still didn't get fluid from the top of the valve.  Should the valve be cleaned or serviced or parts in it replaced?

 

Inside the LSPV, under the top fitting is a component valve. I showed this valve to the the owner of the NAPA store while fitting it for an o-ring. He said the valve looked like a proportioning valve , but he didn't know what an LSPV is.

Dale