odd brake item

"Kryptoknight" wrote in news:R8%nb.199264$ snipped-for-privacy@bgtnsc04-news.ops.worldnet.att.net:

Its a valve that adjusts the rear brakeing based on the load in the bed of the truck.

Its called the Load Sensing Proportioning Valve (LSPV), senses the axle-frame height and adjust the rear brake pressure to account for differences in (perceived) payload in back. That is if you have no weight in the bed, the rear end sits higher, rear brake pressure is reduced to keep from locking up the rear wheels. Put a lot of weight in the bed and the springs settle downa few inches, rear brake pressure is increased to let the rears do more of the stopping work:

so, if i'm braking over bumps (regardless of load in bed), the brakes will be getting more/less braking while the axle goes up/down???

that don't sound good... i can see on a flat surface, but this is a pup, made to be in the dirt, down hills, over logs, etc.

axle-frame height and adjust the rear brake pressure to

have no weight in the bed, the rear end sits higher,

Put a lot of weight in the bed and the springs settle

more of the stopping work:

with the Taco, and the tendency to sag in the rear with minimal load, it usually results in excess brake pressure to the rear and locking up under heavy braking. Bumps aren't much of a factor. It is adjustable.

Probably doesn't react that fast to bumps in the road. I did notice changes in rear braking on steep up and down hills off-road on my 4Runner so I diasbled the load sensing function (see page previously posted). The sensing arm is held in an adjustable height fixture so I can set the front/rear brake bias to work well, then not have it change. Has worked fine for the 6 or so years its been rigged like this. I'll soon be removing it altogether and put in a Wilwood adjustable proportioning valve to work with my rear disc brake conversion, since the LSPV is designed to work best with drum brakes.

The first time I saw a valve was on a friend's Subaru Brat...

Tom - Vista, CA