Regarding a JD 450G w around 2700hrs. Sprocket showing obvious wear. Pins still in spec with a little egg shape. Rails look decent, also in spec. No bad rollers. Grouser pads pretty good. Might need to repair/rebuild the tensioners as one side leaks to a certain point after tightening with the grease but then in an hour or so is back to a little looser than desired. Original plan was to turn the pins. The cost of this including fuel to drive there and back twice isn't too far from new import rails and most say the best plan is to run to failure. But what does this mean? Cause this would mean the sprocket will be soon to be skipping and jumping. What about this idea: has anyone heard of sprocket inserts? These reportedly would weld into the teeth and maybe would allow all the items to last a little longer and then replace all the parts at once. Work demands for the machine have not resumed the pre 2007 levels. But on the other hand, the machine is fully paid for.
Here is my last known source of sprocket liners. Don't know if still in business or not, it's been awhile.
Just wondering how you would get insert to fit the amount wear you have on your sprocket compared to someone else’s sprocket?
I've seen somewhere on this forum where a person was thinking same as you ...made inserts out of drill stem pipe and welded them in. Don't know how that worked out. They were not perfect but I think they worked...he let his chains beat the inserts into the ideal shape after a few hours running
Could you post a picture of your sprocket and idler? Thanks Bob
Saw a guy try this on an old 82-30 terex… It did not end well. His homebuilt inserts shelled out rapidly.
Will get some pics of dozer, it is on a jobsite that we arent working at the moment. Called Pigeon Products, there is a polite message about a delay in response, will give it a week or two.
Sprockets for a 450 Deere really shouldn’t be that expensive to buy new, the labor to put in the liners will be enough to make new sprockets look possible. On a machine that size, you’ll probably have to break the track anyway to make room to work welding in inserts, so you’re almost there to putting in a sprocket.
As to swapping sprockets for new and fixing the tensioner rod and its seal, breaking the track is indeed the method. Was thinking the sprocket inserts would grow the diameter slightly and lengthen the pitch a little because have been told a new sprocket on an old seasoned chain makes the sprocket wear extremely rapidly.....which may be true. But if that sprocket with such a said short life adds some run time to the rails and pins - then that might be of benefit? My original plan was to rotate the pins - who knows, what with tariffs maybe that becomes applicable although it isn't so cost effective compared to new last time I checked the numbers. Run em to failure is the "new mantra". My thinking is if an old engine is slated for a rebuild, why not fix the water pump and continue running it until that time to pull it out....could be a bad example but is all I could think of LOL.
What I tried to say was that the cost of inserts plus welding consumables plus the man hours labor to install them will add up quickly and may equal new or newish sprockets. I think they were the same for several models earlier, used takeoffs could be a possibility.
Appreciated. Guess I went on a mental tangent worrying about the pitch of that old chain being effectively longer and would that create super fast wear on that new sprocket . somehow got the idea the shells would 'grow' the pitch to be more like a worn chain (rails)?
It was several years ago but I bought weld on sprocket rims for a 931B Cat and they were $125 each from Trek. I don't think there's any way you could do it any cheaper. I think the JD sprockets are easy to unbolt too so it would real easy to weld them in the flat position.
New sprockets for a 450G are $150 each
I think this may well be the case. I know if the sprockets are worn the pitch is beyond spec and will likely tear up a new sprocket. Chains wear sprockets, sprockets don' t wear chains. I wonder if those inserts are still available.
$135.00 plus shipping on ebay. https://www.ebay.com/itm/New-John-D...+sprockets&_from=R40&rt=nc&_trksid=m570.l1313
I have seen those sprocket inserts years ago. Have never used them though for a couple of reasons. The way a sprocket seems to wear is the flat between the teeth thins out. If you were to unfold that sprocket out so that is was a flat the length of the pitch is off. But how do you get a piece made that would fit basically an oblong wear spot so that it is properly supported when it is welded in and not depending on just the welds to support it. Also if you add an insert that is say 3/8 " thickness this is going to throw off you pitch diameter which will cause very rapid wear. Don't get me wrong I have had some sprockets water jetted out to fit the pitch of some very expensive and long chain. But you have to calculate the pitch diameter and then have the sprocket built to those dimensions. I just don't see how it would be cost effective to mess with the old sprockets when new ones are so reasonably priced and it would be much less work to change them than to weld in those inserts.
Kinda what I was thinking . You said a lot better then me
I should have added that maybe I have just gotten spoiled working on high sprocket 8's and 9's. When an undercarriage is the north side of $90.000 a set off sprocket segments is immaterial to keep it running for another year until it is complete junk.
Exactly right new sprockets wear faster but are so cheap compared to dumping the undercarriage before its time Just don't let them be skipping and jumping
Most small dozers in this area wear out the bottoms at between 3,000 and 3,500 hours. On small dozers I haven't seen anything pencil out on doing anything but running the undercarriage to destruction. If you are running SALT track it doesn't stretch so the wear on the sprocket just goes down and not onto the tips of the teeth. The small Cat line uses thicker bushings designed to run until they leak oil. The recommendations for awhile was run the sprockets until the chains were at 65% worn and then change the sprockets. Last stuff I was around was just run to destruction. I have seen companies run two sets of chains on one set of idlers and rollers to maximize ROI.
John C You are correct in the fact that you have to weigh out your options. It basically amounts to do you spend that money today or do you prolong it until a later date. It is inevidabley (sp) coming, just depends on how long you want to keep the cash in your pocket.
Updated an old thread - No progress was made since this post started due to work not requiring the dozer. Seems as though I should have busted the track and changed the sprocket some time ago. Now it appears the track adjusters seals are also needing attention - allowing the grease to leak and the tracks go back loose. At this time the sprocket is worn to sharp points. Also learned the sprocket insert fabricator is no longer producing the inserts because the raw material a "fine grain high carbon steel" is cost prohibitive. Somehow I got the idea the inserts would help the sprocket mesh with the worn chain compared to a new sprocket with the worn chain. Thinking I will measure the pitch on the chain and compare it to the specs in the manual and decide to what extent the repair should be accomplished. Will update.
Bet you a $ to a knob of goat styt the chains are stuffed and the ldler is over extended causing the adjusters to leak.
I shall get the section outta my manual and measure the chain for the stretch. Many thanks for this suggestion. Using a round bar to fit tween the sprocket and the chain to pull the track taught, yes? Have been to the local JD dealer and their recommendation for chains etc is a company called ITR. Seems to me rebuilding the tensioner gets me deep enough in it that I have priced the chains, sprockets, roller set, etc.
The adjuster seals are off the shelf parts at any good bearing shops. With the ldler out of the way there's only about an hours work to do both sides. ITR make a good product. Dealers are stealers, save some bucks and give them a swerve .
Put a pipe in the sprocket and tightened the chain....didnt have the manual. Wrote down the number but it doesnt mesh with the dimension attained. Redo in order.
Brought the manual and did the measurements. Chain pitch 25.2" thru 25.7", measured 25.3 Chain link ht 3.5" to 3.26", measured 3.3 to 3.4 Carrier roller 6.0" to 5.5", measured 5.772 Front Idler .96" to .77", measured .836" So far, so good....yes it is worn but within the specs. Then this: the Roller / Pins, FYI feel like a egg (or maybe a pear). New is 2.010. Reverse direction is 1.885, Forward direction is 2.002. The spec for 'high impact' is 1.890 and for 'normal' is 1.820. Bumping into a limit. Seems like a roller turn would alleviate the concern of "old pin in that worn chain on the new sprocket". However am not sure about location of track press shop. Is it true that track press shops dont always perform the "sealed and lube", they do a "greased" turn? And the cost for a new chain may not be that much more than trucking the assemblies a long ways and then paying for the turn. Or....since the pitch measurement shows that is aspect is not near worn out, maybe throw a sprocket into the mix although the rollers look like an egg and delay the inevitable?? Ergo try to discard the chain when all worn out. ~~~~~~~~~~~~~~~~~~~~~~~~~~~ As far as the track tension adjuster not holding, thinking the area should have been cleaned more often but never did take off the covers and attended to that, but yes belly pans are regularly cleaned out but didnt think of the track adjuster - this problem is seals fer sure, and maybe the chrome damaged on the rod too. Marker some black lines on the roller where worn (looking upward at roller) Chip on tooth (thin) Pointed and one side worn more than other Pipe in sprocket to pull track tight for measurement of pitch Thanks for all the wisdom, tips, and suggestions.
Those sprockets are pretty much toast. If 1 tooth chipped more will follow. With the price of aftermarket undercarriage there are very few shops that do pin and bushing turns. I think it's somewhat common for the reverse side of the bushings to wear faster than the forward side. That's how mine are wearing and have seen it on a couple other machines. I couldn't get a real answer from the supplier on why but I know driving in reverse especially at high speed causes the fastest rate of wear. I'm thinking maybe because the sprockets are pulling the chains from the top which tightens them. I also think the backhoe being about 4000lbs. adds a lot more resistance when backing up. On hard ground it isn't bad but on softer ground where it sinks in a bit it takes a lot more power to back up because it's basically trying to climb out of the depression at the heavy end. Going forward with the front end much lighter is much easier and takes a lot less power.
Oceanobob - The items you've marked with black marker are called bushings, the pins go through them to hold the track together. The bushings are very worn, probably because of abrasive soil. In the old days of track shops everywhere and expensive undercarriage, we'd pull the track chains off at the wear point yours are at, take them to a track shop, and get the pins and bushings pressed out, turned 180 deg, and then pressed back in. This then presents a new wear surface to the sprocket and takes the wear out of the track chain pitch. We'd install new sprockets and go on to get another 1500-2000 hrs out of the other side of the bushings and pins. The undercarriage would then be scrap. Unfortunately in todays world, there are very few track shops left, and very few people turn pins and bushings any more, because labor costs have gone ballistic, and new undercarriage has become much cheaper. Your easiest option today is to keep driving until the sprocket teeth just become bumps and the sprocket starts jumping inside the bushings. That will still take a while. Then just buy all new aftermarket undercarriage.
@oceanobob - this is the process that @OzDozer is describing. As you can see it requires expensive hydraulic tooling that many track shops had in years gone by but today is nowhere near as common. It is a labour-intensive process which is why it isn't cheap, and probably one of the reasons it fell out of favour. First the complete track chain has to be disassembled, then reassembled again with each bush having been rotated by 180 degrees. Usually new seals for the bushings are also installed at the same time.
I haven't seen bushing turns in 20 years or longer. It isn't cost effective any longer.
Bob we put ITR chains, sprockets and pad bolts on our 321DL a couple of years ago. We've had zero issues and much less than Cat.
It's only cost-effective IMHO if you are in a market that has a low hourly labour cost, or if your time costs nothing then build a track press and you do it yourself - like this guy on YouTube .
Do you have the capabilities to work on this undercarriage yourself?
Another way of getting a little more life out of the sprockets is to swap them from side to side. One side will be worn more than the other and believe it or not it's all to do which hand you write with.
Since it's a small tractor no sense in going through the labor and not just buy new segments IMO. Aftermarket segments are very reasonable for a 450.
We did get a repair quote for each track or chain "bushing turn" at around $1400 to $1500 plus parts (half a set of bolts or all the bolts to the pads). ITR chains are about $2000 and I was assured this is notably less than JD OEM. The turn process will also not be a true repair per se because the new "seals" are not those like new with the vacuum grease application - this is not attempted: some grease is manually applied to the roller instead. Nicknamed a 'wet turn'. When comparing new chains to having these bushing turned: Not possible to save the difference due to the fuel and delivery cost to haul track back and forth to their shop, plus the misc parts reduces the difference a bit. In conclusion: let's say there are three or four parameters that were in spec and one parameter was end of life. Had I not been thinking 'bushing turn', that [now] olde skool technique (for that one parameter): I would be less pained. Clearly am aware of the 'gotta do it this a-way cause the cost of labor otherwise is a worse idea'. Always known and been reminded "if you keep that machine make sure you save for the undercarriage day!" Looks like we are off to the races! Kicking the can no more. I presume: if doing the rebuild, include all the rollers and the idler and of course the sprocket. As to this 1998 JD 450G model: The chain and the sprockets are about half the part bill: the idler, top roller, bottom rollers .... comprise the other half the bill. Budgeting $9k for complete list with an unknown is the condition of the chrome rod for the grease seal. It is interesting because of the logic quandary - if turning the bushings? then one keeps all the existing rollers and idler; but if putting new chains? then one must/should do "all new". Therefore while the bushing turn may not be the less cost method when looking part by part, but it allows further usage of additional old parts which in turn lessens the overall repair bill and staves off a notable amount. Hmmm....
You could just throw new sprockets on it and have at it. You have to remember that here on this forum, most of us are trained to put out the best final repair. We usually don't recommend short cuts...........it's not our nature. As a self-employed tech, I can only consider a short cut if asked and approved by my customer..........outside of that it gets what I say. Could you possibly run your undercarriage out longer just by changing the sprockets? Sure, you can.............it's been done many times. It's just not something I can recommend as a solid repair that will last you for years.