I've gotten a bit behind in the updates....here they are!
I left off where we had finished the steering box rebuild up until the point where the bearing and bushing that support the ends of the sector shaft needed to be replaced. The bushing was available on McMaster (steel-backed teflon coated sleeve bearing) but over twice as long as needed. These sleeve bearings are split at one point, and we were afraid of that split catching on a standard lathe tool bit and destroying the bearing. Pat's dad suggested we turn it on a lathe but use a Dremel as the cutting tool. We did that at a robotics meeting, and it worked like a charm.
The bearing ended up being a special order. As soon as I told the sales rep for Eastern Industrial that it was for a steering box, he told me that anytime he gets a bearing request for a steering box, its a weird size. Turns out this one was no different. Wallet was a bit thin after that one...
Armed with both bearings, we got back into the rebuild:
This weekend was quite interesting, as I was sharing the bay with a 70 ton Grove crane that had been hydro-locked.
The needle bearing was an odd size that was thinner than most. Not much meat to the outer race, and no inner race. To minimize the press force required, we chilled the bearing in a freezer (on the coils) and heated the box casting until it was almost impossible to touch. Bearing pressed in with very minimal force.
The bolts holding the sector shaft cover in required torquing to over 200 ft-lbs. Pat had to bring out the BIG torque wrench.
Here is your's truly performing the final benchtop tests to set the pre-load and backlash. The final numbers for input-shaft torque were right in the range suggested in the manual, meaning we probably didn't screw it up!
EDIT: While performing this procedure, I figured out that it was VERY easy to set the pre-load on the gear mesh and then torque the lock nut without realizing you had ALSO spun the pre-load adjustment screw enough to triple the pre-load. This probably explained why the original box had failed after only 4500 miles....the wear on the sleeve bearing was consistent with enormous pre-load on the gear mesh.
If the original assembler forgot to check the input-shaft toque again after setting the lock nut.....it could have left the factory with a destructive amount of mesh pre-load.
Moral of the story.....always double-check critical measurements!!