I'm trying to adjust the tracks on my D6 9U. I have the manual screw type adjusters. Do you have to jack up the tractor to make adjustment easier? My adjuster screws are very difficult/won't turn. I did loosen the pinch bolts. I got one side to move with the help of heat and a seven foot long bar on a 24" pipe wrench. The grease fittings were obviously neglected by the previous owner. The other side I have yet to get to turn. Is it because all of the weight of the tractor is on the tracks? Is a total undercarriage disassembly necessary to clean the threads on this adjuster screw? I would like to get it cleaned and accepting grease. Thanks.

Did you loosen the two bolts that clamp the two arms to the nut? They have to be loosened so you can turn it to ajust the track. No you shouldn,t have to have the tracks raised off the ground to adjust it.

What model 9U do you have. Early ones had two pinch bolts, later ones had four, latest models had yoke arms that were part of the idler assembly and required splitting the tracks to remove the recoil assembly for the repairs your referring to. The earlier recoil assemblies could be removed without splitting the tracks. Also the nut (housing with the thread and grease zerk) guide and screw can be unbolted from the spring assembly so that it is not necessary to mess with the spring. Yes, they are a bitch to work on.

Ooops, All the 9U's had four pinch bolts, ya have to go back to the 2H models for the two bolt arrangement.

I forgot to say, if you are adjusting it out a ways, even to the point of being too tight if necessary, you can wire brush the exposed threads. the ones up inside the nut aren't usually so bad as the ones just inside where dirt and water have gotten to them. Grease while it's hot.

my 9U is a 9U59xx. It has 4 pinch bolts, spoked idler, and it looks as though the back of the nut housing can be unbolted from the spring assembly. If I unbolt that am I going to recoil the spring? I don't feel like "wearing" a spring of that size.

Don't blame you for not wanting to wear that spring:D
They are two different assemblies that separate at the nut/spring. The spring has it's own retaining bolt with the head in a pocket at the back of the nut.
Check to see if your yoke arms bolt to the front idler bearing blocks (two bolts each arm) or are one piece (part of the bearing block). The parts manual does not show it right for your serial number and could be interchanged between the two styles. If they are one piece you need to split the track to remove the adjuster assy. If the arms unbolt the assy can be removed without splitting the track and making use of a wedge between the idler and the track frame. I can post some pictures when/if you get in to it.

Just out of curiosity, where are you at with the track adjustment dimension?
The D6's are not very forgiving if you over extend the adjustment screw as it results in stripping the threads in the nut.

I was not thinking right on the yoke arms. All the 9U's had the one piece arms, it's the 4R, 5R series that had the bolt on arms. They still can be interchanged though so it's worth a check. Bad news is you will have to split the track on yours as mentioned unless it has the earlier arms.

Thanks Old Magnet. Yeah, my idler yoke assembly appears to be a one piece unit. I'm at about 7 1/4". I am going to be looking at some pretty heavy undercarriage work in the future I realize. My sprockets are pretty pointed and the some of the bushings are worn through. Rail height is still about 3 7/8" and pads and grousers are still in decent shape.

Beware of recoil springs that have the track adjuster "nut" pushed up against the guide in front of it. those have a broken bolt and the guide is holding the tension of the spring.

I have one like that and haven't gotten around to doing anything about it, but I sure am not going to be unbolting the adjuster nut from the front of it. I was thinking about fabricating a stop sort of like the later tractors where the spring bolt is kept slightly slack and the stop keeps the spring at the correct length. Anyway something stronger than the guide thats holding it now. I can back up with something in the sprocket to get the right length on the spring.