Lever and block on rear Differential

[Coastal NC Jeeper]

Hello All,

On my 1989 Comanche 

Can someone please educate me on what the articulating lever device connected to the rear differential and to a lever on a block above the differential with rear brake lines attached is for? 

[eaglescout526]

Its the rear proportioning valve. It articulates and proportions rear braking power for when you have the bed loaded. The more in the bed, the more power that goes to the rear brakes. Neat little device that was conceived before modern day brake controllers. Ive always wondered how they can fail.

[scaleless]

9 minutes ago, eaglescout526 said:

Ive always wondered how they can fail.

If the bed sits unloaded for a long time, the piston inside can seize up in the closed position.