Old Magnet,
Thanks again. I have a couple more questions. Some may be dumb- who knows!

1. On ordering the seals- Do I ask for (2) 8M3992 seals as shown in your first picture, or (2) 3B5730 as shown in your third picture? Which seal is "best"? The duo cone or the original Cat part? (remember I am only working on the left side of dozer- for now)

2. On the adjuster bolt/nut- Do you have a link or name of a good place who carries that bolt? Also, if I remember right the threads were better in the nut than on the bolt. I would still feel better knowing that the threads are "like new" in the nut as well. Can a machine shop clean threads inside that nut? How do they do that? Or is a new nut the ticket?

Side note- my closest dealer is about 60 miles away. Mail order is easiest for me, but not mandatory. thanks again.

Oh yeah, now I remember the other question.

On the sprocket fit- What should I do? What would you do? Run it? Look for replacement? Any suggestions?

Joel,
I would find a good used sprocket. You could probably get one with a worn out ring for very little and transfer your ring to it, but if you could find a good one to start with. it could save the welding. The male splines will be worn some so you will want a good sprocket hub to go with them.

The nut on the adjuster can be cleaned out if someone will take the time to chuck it in the lathe,(may need a fixture for security) but the threads are usually protected by being inside as opposed to the external threads on the adjuster that stick out as the adjustment is made on an old track, and are running up inside the guide and exposed to all the dirt. I would take the torch and heat it so it burns out all the old grease, scrape it a bit with a wire etc and try it as is. Make sure the grease fitting/port is clear before you put it back on.

The internal thread cutting is done with a boring bar on something that big. Same thing that will make a smooth bore will thread if the tool is moved a precise distance along the bore for each turn of the chuck.

CCjersey,

The only problem is when I look at my splines on my sprocket they look good to me. How am I going to know that the used one that I find is going to be any better? You don't happen to have one do you? Or maybe you might have a lead on one? Thanks.

Hi Joel,
I know things are getting confusing.....it probably will for awhile.

To do the duo-cone upgrade one 8M3992 is required for one side of the tractor.

To do the bellows seal replacement two bellows assy. are required for one side of the tractor.

Now I'm going to confuse you even more.......
I know the old style metal bellows seals are no longer available but if you were to show a Parts man what you have they would know the latest upgrades. So far as I know you could expect the following:
3B5730 will upgrade to a 5H426 (rubber type bellows)
The 1A4088 wear washer is still used and can be turned over and reused.
The 6B6020 gasket is now a 7F5015
The remaining required gaskets, seals, and grommets should come with the new seals.

The cement for the 7F5015 gasket is part # 5H2471

For me, I like the duo-cone seal arrangement that reflects current production.

On the sprocket/hub thing.....you could waste a lot of time...and money trying to match used parts with no guarantee of fit. To me the only way you could come out is to be able to drop the hub into a used sprocket and check to see if it looks like it will hold spec. under installed conditions.........or get a used hub and sprocket match that is a known fit. Again there is a reason for the controlled depth of the press fit as there is a limit to how much displacement the bellows seals or duo-cone can handle.

The adjuster bolt part # is a 1F9490 screw.
Try Regal, Costex or Heavyquip.....or do a parts search on MachineryTrader.

OM,

So if I'm understanding you correctly, It's not the spline stripping out on the shaft/hub that's the problem. It is that the bellows/duo cone might not seal?

Actually some of each....the press fit tapered spline requires full area contact to hold. If you ride up on the unworn section at the expense of loosing contact area the press fit will not hold and also effects the working range of the seal.

Also brings up another question. With the seals that bad I'm wondering if much of any lube was being retained in the final gears. Did you happen to notice how much gear back lash there is?? When you have a chance, pull the drain plug and check for metal particles or pieces.

Is there a measurement for gear backlash? What exactly is it? I constantly was filling the finals. It was like- check the gas fill the finals.

Backlash is the amount of slop (or no load transfer) between gears when you rock them back and forth (rotating)......usually checked by rocking the sprocket when still on and tight.
Can be measured when gears are exposed but normally done by feel and judgment in this case.
Good gears have barely precipitable backlash. They are pretty forgiving but there are limits and the check can be an indicator of more serious problems.

There is some slop there when you rock the sprocket back and forth. Don't know how much, I have nothing to compare it to. Is that slop between the bevel gear and pinion? I'm starting to get this sick feeling inside!