Brake System Modifications  (Continued)

Brake Proportioning Valve (BPV) Bracket modification

If you lift the rear suspension (not a body lift), you will also need to raise the Brake Proportioning Valve (BPV) lever approximately the same distance. This is accomplished by fabricating a flat bracket that will reposition the BPV lever to a higher location in relation to the rear axle. Via the lever, the valve "senses" the rear of the truck frame in relation to the rear axle so that when the rear end sags due to a load, the braking power to the rear increases accordingly. If you add a suspension lift, you move this lever position further away from the axle (opposite of sag) so the brakes will not be getting the amount of power that they are supposed to at stock suspension height. You don't need to be concerned with this if you install a body lift without a suspension lift. Special thanks goes to TTORA member Mike Burby (AZ Chapter) for making this bracket for me.

See the photos below for descriptions. (Click on photos to enlarge.)

Here is an overview of the location of the BPV components.

A closer look at the BPV. This photo is taken from behind the rear axle looking at the left side of the truck

This photo shows the new bracket and the relocated lever

When I installed the new bracket, I had a problem with the fasteners for the lever hitting the adjacent bracket and hardware that is mounted to the axle tube. So I had to install several washers to shim out the new bracket enough to allow the top two lever bolts to be installed.

Here is an alternative to the shims. (photo courtesy of Mark Griese) It consists of a bracket with the mounting holes offset to place the top of the bracket at an angle to avoid the conflicting hardware.

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