440 Sprocket Spacer ?

Roger440IC · Post by **Roger440IC** » Thu Oct 30, 2008 12:35 am

Can anyone give me some undercarrige advice? I replaced my rear sprockets, four rollers including the rear roller on each side, one of the front idlers and put on a set of tracks with almost new pins and bushings. When I was putting it together I noticed that the rear sprokets were close to the inside flanges of the rear roller on both sides. I also noticed that rthere appears to be only about 1/16" of shim material, or less, between the rear cross bar flanges and the track carrier. Also, the bolts holding the carriers to the cross bars are rusted really bad. So given that the sprokets didn't appear to be touching I put it all back together.
Well I've driven it a total of about 800 yards and the inside face of both sprokects has a 1/16" groove cut in it from hitting the rollers. The right track also rode up over the inside flange of the rear roller and down into the center of the link. By loosening the adjusters, jacking up the right side of the dozer and then pulling the track to the outside I was able to get the track set straight again.
The situation now is that the sprocket has about 5/16" of clearance on the outside and is touching the inside of the rear roller on both sides. Can I make up 1/8" spacers and put them between the sprockets and the final drive flanges? Any suggestions on this would be greatly appreciated. Thanks, Roger

Gil · Post by **Gil** » Thu Oct 30, 2008 11:11 pm

There were two different dish sizes for JD440 rear sprockets. The later model crawlers (after serial number 456802) had a larger final drive housing. To keep track and carrier dimensions the same, these later crawler sprockets had a more shallow dish, reducing their overall depth by about one inch.

You could have the wrong sprockets. I think that is doubtful because your setup would be off a full inch. I have however seen spacers used to extend the shallow dished sprockets to fit an earlier model crawler. It seemed to work but I wouldn't want to comment on what the torque would do over time. I cannot remember if the dowels were replaced with longer ones or not. In what you are proposing there would not be that much of an increase though.

That may answer your question, but I do not know if that is your problem. It seems more likely that the bearing on your final drive axle is failing and the sprocket is cocking inward as it drives the track. If that is the case you should be able to measure a difference where the rear edge of the sprocket is kicking out and the front edge is kicking in. If you remove the track or take the weight off of the sprocket, you may be able to grab the sprocket and wiggle it in the bearing.

Roger440IC · Post by **Roger440IC** » Sat Nov 01, 2008 1:40 pm

Gil, I checked for play when I had the final drives off but I didn't try it again after I put the sprokets on. Good thing to check but I hope it's not that! I'll jack it up, loosen the track tensioner and see if there's any play. Do you know if I can pull the sproket off without breaking the chain? Thanks for your help. Roger

Gil · Post by **Gil** » Sat Nov 01, 2008 6:42 pm

I have never tried to get a sprocket off with the tracks still on. Even if the track was super loose, you would need to keep it supported above the top of the sprocket teeth somehow.

Seems a lot more difficult than just hammering out the pin. It is easiest if the track is moved so the pin is positioned to the rear of the crawler three fourths of the way down the backside of the sprocket (if it is the right hand track that would be visually in the 7 or 8 o'clock position on the sprocket). That way you can get a good whack at it getting it on and off.

You may not need to remove the chain off the sprocket at all if you just jack up the crawler and take the weight off the track and relieve the tension by collapsing the adjuster. Then you can put a crowbar against the sprocket and see if you can wiggle it.

Roger440IC · Post by **Roger440IC** » Sun Nov 02, 2008 10:04 pm

Thanks, I'll let you know what I find when I get over to the crawler in a few week. Roger

Roger440IC · Post by **Roger440IC** » Sat Dec 06, 2008 5:13 pm

Gil, I finally got this sorted out and the sprockets are now centered w/r to the rear rollers. I fabricated two 16 guage shims/disks to fit under the sprockets for each side which gave me about 1/8". I measured the dish from the sprocket faceplate to the centerline of the teeth on both the old and new sprockets and this is where the 1/8" difference appears to have come from. The old sprockets are pretty worn and I had to assume that they wore equally from both the inside and outside.
You were right when you said that driving the pin out would be easier. Even with a chain-haul holding up the track I was unsuccessful when I tried removing the rear sprocket after loosening up the tensioner. I even tried to remove the track over the front idler but that didn't work either. Realigning the links to drive in the pin took a bit of time but I guess I know better for next time. Thanks again for your help, Roger

The Fireman · Post by **The Fireman** » Fri Dec 12, 2008 2:32 pm

Glad to hear you got it straightened out, I dont know if it matters on these old crawlers but as a rule on new ones a double flange roller should never be put 1st after the sprocket. The double flange can interfere with the sprocket, I know for a fact that this is the case on a 700H, when the track frame pivots the double flange roller crowds the sprocket and dose the same thing you are discribing. I made a mistake and did this once

Not a fun situation to explain to the boss

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440 Sprocket Spacer ?

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