Thanks Juiceman!
Today I ran the tractor for 30 minutes and pushed some logs around. It's not leaking oil from the crank case or the final drives. I topped up the oil level while the main engine was running. There may be a very small diesel fuel leak - I need to clean the engine really well, and then observe it again.
There is a coolant leak around the pony. The pipe connecting the main engine coolant to the pony leaks at the connector 4B3041. Does anyone know how this thing works? I assume it clamps down on the pipe in some fashion but it isn't obvious.
There may be other leaks, it's not clear. I don't know whether the coolant on top of the pony was coming from failed gaskets or getting sprayed from the leaky pipe fitting.
The big downside is, I couldn't get it to turn right even once, so there was a lot of backing up and engaging the left steering clutch/brake. I believe the right steering clutch is releasing ok - when I pull both steering clutches, the machine comes to a stop. So, the problem is that the right brake won't engage. (I also tested this by engaging the brake when the machine was rolling in neutral.)
As I was talking to the previous owner's widow, she said she just remembered that the last time her husband tried to run the tractor to clear snow (probably about 4 years ago), the steering gave out on one side. So - this problem has existed for a while!
The manual is fairly clear about how to adjust the brake, but it doesn't explain how to get the clutch compartment cover off. How the heck do you do it? All the bolts came out easy, but it's so tight you can only lift it up a few inches on the inner side. What else needs to be removed to get the cover out?
This picture makes it look way more roomy than it really is haha. But the larger cover is jammed between the hydraulic boost pump (left of the photo) and the seat support (towards the front of the machine).
I don't think the fender is removable - it looks like it's welded to the frame! Though two of the bolts have to come out to remove the clutch compartment cover - they both look a little black from previous removal.
From right under the seat, you can see that the brake locking lever is actually above the steering clutch cover. You can get the lever mostly out of the way by locking it, and I did manage to get the cover up above the lever, but it was jammed in place and I couldn't figure out how to remove it.
The manual talks about adjusting the steering clutches while the engine is running, so presumably it's possible to do those (and the brakes) without removing the seat. But how?!?!
Any advice very much appreciated!