Rebuilding a JD 440C

Hi folks, new crawler owner from Manitoba here.
Picked up a JD 440 crawler loader a few weeks ago and have been having a blast with it. One annoying thing is it tends to throw the right track. I assume this means it's rather worn out on the rollers and probably chain.

Anyone know what size the rollers are supposed to be? And what height the chain/rails should be as well?

I work in a small machine shop so I can do all the work myself for a rebuild, just need some extra data.

Thanks

I've been looking through info I have for a 430 to see if the roll diameters and chain rail height are there and it does not appear it is. The manual does give the OD of the chain bushings as 1.559" to 1.5635". I don't have a 440IC or ICD service manual to check to see if those specs are in it.

I did find a chart I had saved, from a web site that is gone now, that has the dimension and directions to measure the chain for internal wear. It will not be surprising if your chains are worn out internally. Hopefully some one will have the info you are looking for.



How tight are your tracks? You should have about 7/8" sag between the sprocket and top carrier roll and the same amount between the idler and top carrier roll. If the track frame is out of alignment it can cause issues keeping the track on. Internal chain wear can let the chain "snake" and lead to coming off.

If the Operator's Manual (JD # OMT544458 prior to SN 448001, OMT54859 for SN 448001 and after, and OMT73459 for the 440ICDs) and the Service Manual (JD # SM2023 for spark ignition or SM2028 for Diesel) didn't come with it you should get them.

You may know this. The common fix for undercarriage on these is to replace the components with JD350 components. Due to bolt up differences the 440 sprockets have to be re-rimmed using 350 sprockets.

Lot of times it is just the pins and bushings are worn. If your rail height is good, they can be rebushed. If not, then you are looking at rails too.
Lavoy
jdcrawlers.com

Thanks!
According to the chart I'm right at 100%
worn out. I'm sorta surprised it's not
more.
I've got a service manual for the machine,
but it doesn't go into detail on roller
size or rail height.
Rails are measuring between 2.980 and 3.050
If I had to take a wild guess I'd say it's
supposed to be 3.125" tall, cause 3 1/16"
is just odd sounding. Lol

Was sorta wondering about weld building and
milling the rails. Anyone try that with
success?

Those are the same sizes I've got for
bushings in my manual. The bushing on the
track check out at around 1.520

Was kicking around the idea of turning new
ones out of 4140 HTSR at work.


Tracks are at 1" slack (supposed to be
between 7/8 and 1 1/8)

Unless you heat treat them to about 60 Rockwell, it's a waste of time and steel. Have had a couple tracks in over the years to rebuild for guys that had had soft material put in. Lasted very short time frame, and made the rails non-rebuildable. Threw a gorgeous set of rails in the scrap dumpster once because we couldn't save them.
Lavoy

If you've got a good track shop around,they should be able to use the dimensions off your rails and get you a new set of rails. Same goes for the bottom rollers.

It's been too long ago for me to remember what the rails fit, but that's how Dad got a new set of rails for our 440 IC.

I know he found bottom rollers that matched too, but I think we had to drill the bolt holes out to a larger size for them to fit. That isn't that difficult to do..... especially if you've got a machine shop.