Good deal! Nice to have one running, even if it still has some problems!

First thing to do on the steering is to adjust clutches and brakes to spec and drain oil from the dry steering clutch housing on each side. Won't hurt to check the main clutch while you're at it. It is also a dry clutch and came from the factory with a plug in the bottom to keep water and mud out.

If you mean that it will steer to the right when you back up, but not when going forward, I think you're right about the brake on that side being involved.

However, you have to remember that to turn to one side, the other side has to be "strong" enough to drive the machine by itself. Sometimes one side steering clutch pack is sticking, out of adjustment, oiled or just plain worn out and the first thing you notice is when you pull the OTHER clutch, the machine just stops pushing.

Well Done ! Welded,epoxyed, siliconed . good insurance. Check your radiator vent .
Some localized heating with a small gas welding tip on your packing nut will help.
Cant remember which way to loosen but the operators book says tighten the direction the shaft is turning.

get it loose and stuff some more rope packing in there let it drip some till the rope breaks in .

You have a ccu so its hard to see the clutches. may be some oil in there so check your drain poke in there the dirt dobbers love to close them up.
If its oily, a washing will help cure your ills.
Now that its moving again youll have more needed insperation. Like the famous indian chief said( I dont remember his name) We shall persiveere!

I know I will have more questions later