There are really tow seals in there, one that you will see first is a dust seal to keep dirt from getting in and in a little deeper is a high pressure seal, that is the one that is leaking. And unless you want to get into rebuilding the steering box I'd swap it for a rebuilt at a local auto parts store. They won't have it waiting for you but can order it.

There are two arms. Idler arm and pitman arm. Both are connected to the idler-arm.

** You have a steering box leak.

LISTEN TO RON A pitman arm but that won't stop the leak. the steering gear itself is the leak. a new seal for sure but wear inside the steering gear must be repaired or gear replaced.

Pitman arm

on my 69 f 100 a seal is blown behind the arm that moves the tie rods. any fluid that i put in the power steering pump comes out behind that arm. what is the name of the arm i'm talking about and the seal behind it?