Steering Box Identification Help

[sargentrs]

See this article for a full explanation https://www.fordification.com/tech/propvalve101.htm. Without knowing the actual part number, year/model, it's difficult to tell which you have there. If it's '67-'72 F100, which I believe it is, it's called a pressure differential valve. This valve has a spool in it that moves from side to side monitoring the flow of brake fluid to/from the brakes. It contains an electrical switch, centered on top with the plastic connector, that lights up the brake warning light when the pressure becomes unequal. There are other similar valves, that actually control the pressure and can apply more/less pressure to front or rear, called proportioning valves, but those were not available as standard until '73 and used in front disc brake applications. Stock bumpsides only had pressure differential valves to operate the brake warning light on the lower left corner of your dash, close to the driver's door. Given the age and condition of yours, it'll probably need rebuilding. Just a couple of seals/o-rings and usually not difficult to do although they can be stubborn to disassemble.