4" Lift/Rear Brake Proportioning Valve
 

Does anyone know if a lift affects the brake proportioning valve on the rear of a 1st Gen 4Runner. Its that little valve that senses the load and adjusts the rear brakes accordingly. Does it have enough adjustment in it to compensate for the lift, or do I have to remove it and plumb around it? Anyone have any experience with this?

Suspension or body lift?? Since you said 4" I'll assume suspension. Yes, a suspensiuon lift affects the LSPV (Load Senssing Proportioning Valve). You can make a lift bracket for where it attaches to the axle. Just make it the same height as you lifted (4"). Take a piece of 1/4" plate (or there abouts) and match the bolt pattern. Then match it again 4" higher. Attach the bracket to your axle and the LSPV arm to the top bolt holes you made and your set.

BTW: I do not believe there is enough stock adjustment on it to compensate for a 4" lift. On a body lift, the LSPV isn't affected

You bet it does!

http://www.4crawler.com/4x4/4R_suspe...ortioningValve

Thanks guys for the help, does anyone know why I wouldn't be getting brake fluid to my rear brake wheel cylinders? I pulled off the lines while changing rear wheel bearings, and no fluid came out. After install, went to bleed and nothing again. Also, I still have full pedal pressure and the truck still stops fine on the fronts alone. Any ideas?

Kink'd or pinch'd line?

I don't know if you can set the LSPV for no rear brakes but maybe it's just way out of adjustment. Doubtful though.

I don't think its a kinked or pinched line, but i don't know what the deal is. Is it possible that the LSPV is clogged? How is the brake fluid distributed, could there be a master cylinder problem? I haven't looked at a schematic for the brake fluid, so I'm not sure how it reaches the rear, with the LSPV and everything else.

According to the FSM, you need to bleed the LSPV and rear brakes while the vehicle is on the ground. So if you had the weight of the rear axle when you did this work, that might explain what was going on.

Thanks Roger, I'll give it a try and see what happens!