[cleveweld]

The steering boxes in the early Tempests were filled with gear oil to lubricate ball bearings and pitman shaft bushing. As the pitman shaft and steering shaft seals age they begin leaking and steering box will no longer hold gear oil. Filling the steering box with grease will be mostly ineffective as the grease can't flow to where it's needed.
The solution is new seals and pitman shaft bushing. With 101K miles on the car I decided to replace the pitman shaft bushing. The seals and bushing were used on many GM cars of the 60's so they come up on Ebay regularly and the seals are listed on Rock Auto Parts but I didn't see the bushing there.

Pitman shaft seal: 5670325
Steering shaft seal: 7802160
Pitman shaft bushing: 266316

I completely dismantled steering box so I could clean all the old sludge out of it. The steering shaft and carriage assembly might be able to be cleaned by soaking in a solvent rather than taking all those ball bearings out. I painted everything while apart.
I found a socket to use to press old bushing out. Once new bushing is pressed in the new seals can be installed.
The steering shaft is assembled into housing first. I put a little bit of gear oil on both ball bearing assemblies so it wouldn't be going back together dry.
The large adjuster plug will need to have its threads sealed or they will leak. I used a brush-on paste. Don't cote all of the threads because about 1/2" sticks out where locking ring goes on.
I also made a new gasket for the top cover from gasket material I had on hand.
My steering box has been holding gear oil for about 3 years now and hasn't leaked a drop.