Do our trucks have something like this? Something that measures how much load is on the truck, and makes the braking pressure adjust accordingly? I know my friends Tacoma has one (on the rear end) and he made an aluminum bracket that moves it down 2 inches or so, and before he could not do a power brake, because it would make his truck think it had a huge load on it, and would increase the brake pressure, but after moving it down, he can do one easily. Do we have anything like this?

 

On a ford they are usually on the frame under the driver side seat, ot thereabouts. Its kinda rectangular block and has 4 or five tubes goin into it.
I don't think droppin one would allow you to powerbrake though. The purpose is to distribute the same amount of hydraulic pressure to all 4 brakes, since the booster is on the driver side and has the shortest length, the front driver side would have the most pressure, the proportioning valves just regulates the same pressure to all 4 corners

 

I was just wondering. I have no problems doing a power brake Except I have that damn 1 wheel spin, I hate my open diff.

 

I'm a Toyota Tech, what the Tacomas have is a load sensing proportioning bypass valve. It changes the pressure applied to the rear brakes depending on how much weight is in the bed of the truck. When there is weight in the truck the suspension squats pushing down on a lever attached to the valve. What he did by moving the rod down is reduce the pressure to his rear brakes, the truck probably wouldn't be very safe to drive in the rain or snow anymore. Also once you mess with them it is a pain in the butt to get get them adjusted right.

-Jon

 

Well his truck was lowered, and that is why he had to adjust it. You know it thought the bed was real close to the axle so it applied alot of pressure.

 

Nissan uses those too, but I have never seen one on a Ford truck.(At least a pre 97 truck)

 

I'm pretty sure our trucks don't have a load sensing lever that changes the proportioning valve, but I wouldn't put any money on it

 

The Ford trucks just have a standard proportioning valve that sends a given percentage of the pressure to the rear wheels. Most newer vehicles now just use wheel speed sensors, yaw sensors, deceleration sensors, etc and regulate it through the ABS actuator.

-Jon