350U PTO leaking at input lever

I have a 350U that is leaking oil at the shaft that turns the pto on and off. I disassembled everything and took out the shaft and bushing that control the bands. This is the shaft that is leaking. The feel on the bushing on the shaft feels good, with minimal play. The problem is when you assemble it and put preload on the bands with the adjusting screws, the bands push down on the shaft, causing it to cock in the bushing.The far end of the shaft moves up just enough that you can see that the lower part of the seal isnt touching the shaft anymore. This lets it leak oil. Anyone ever seen this before? It appears to just be a poor design. The shaft and bushing only had about .005"clear, so I dont think you could do much tighter...
Ideas?

Hi, Mike.

I replaced that seal on my 350U this past spring, and my 300U is currently in the garage with the PTO cover off and the linkage disconnected, so I've sort of been there...

I haven't come across your particular problem (yet). On the 350, I remember thinking how nicely that shaft fit in the bushing -- no slop whatsoever, and it hasn't leaked a drop. So maybe part of the answer is that absolutely no slop is allowed there.

If your shaft is cocking enough to lose contact with the seal, that's a lot of misalignment for a short shaft. It doesn't seem like a big wear item (only a few degrees of movement, up to several times per day). That makes me suspect damage. (I've seen just about every part broken in 300U/350U PTO linkages. It's almost like operators get irritated when the bands need adjustment, and just horse on the lever instead.)

Is there any chance the bushing has a longitudinal crack? That would be hard to detect, but could allow that kind of cocking. Same thing for a small crack in the housing, which would allow the bushing to shift.

If you're using a new oil seal, does it allow as much shaft movement as the old one did? If you're using an old seal, has it become too stiff over time?

Just some thoughts. Good luck, and please let us know what you find out.

Mark W. in MI

I had it all apart and didnt see any cracking. I think your right on the idea that there just isnt any room for play. The fit was good for a bushing, but in this case maybe not good enough...poor design if you ask me. The bushing is $50 new from the dealer...

Hi, Mike.

If there is a crack, it may be too small to see until you put some stress on the mechanism (like when you pre-load the bands.)

Poor design? I can't really disagree with that. If we define a "good design" as one that does the job, lasts a long time, and is reasonably affordable to buy, operate, and maintain, then this setup appears to fail at the last point. With dealers demanding north of $600 each for the bands (which IMHO would be seriously overpriced at $150), I don't think that's reasonably affordable maintenance. Fifty bucks is plenty for a bushing, too, but you'd probably have $150 worth of time (yours and the machinist's) into it if you had one made from scratch. It seems that there would already have been other, better, proven ways to start and stop a PTO when these tractors were designed.

I still love the tractors, though, warts and all. They kick some serious booty out in the field!

Mark W. in MI