So I'm in the process of getting things together to rebuild the undercarriage, a few questions I think I can handle most of it, seems pretty straight forward except....... The rear sprocket, debating on replacing the whole thing or just the maybe outer section. Have seen where you can buy the toothed section. I can cut and weld so that doesn't concern me, what does is that it's already been done on mine, not sure if it should or can be done again, any consensus???? I would prefer to just replace the whole thing, the price isn't an issue, I have a complete service manual and it talks about using a hydraulic puller to remove it and a hydraulic ram to re-install it....can it be done with out the use of the hydraulic puller and ram???? That would be the main stumbling block in replacing the whole sprocket Thanks for any input Tom
Tom, A new sprocket can cost a small fortune,which is why weld-on rims are popular.The Japanese manufacturers are very good at charging a lot in exchange for a little.... I'm about to pull the R/H final on a D31S-16.Book shows a puller is required. I saw a guy pull a sprocket on a 931 with a hand-powered puller. Jim
I have been viewing this forum for a few years and decided to join to post my experience to this post. I have pulled the sprocket on a P-20 by using a 20 ton bottle jack. With a helper to hold the jack, I threaded a heavy chain through the holes in the sprocket then over the base of the jack. Then I pumped the jack to tighten the chain so the jack would support it's self. The sprocket is press fitted on to a tapered splined shaft and it takes several tons of pressure to pull it. I stood to the side (this is important) and pumped the jack up then took an 8 pound sledge hammer and hit the sprocket once and it popped right off. I know there are some mechanics cringing out there after reading this but it was all I had and it worked. You may choose or not to try this procedure. Leroy
I was kind of thinking something like that, just looking for others that may have done it without a puller. I'm shying away from a weld on outer piece for the reason that mine has already had one welded on
still looking for input on the weld on sprocket rims. My D31 has already had a welded on sprocket rim. I need to figure out whether to go with another weld on rim or should I replace the entire rear sprocket. Just not sure if it's okay to cut the old welded rim off and weld a new one on. If so any advice on the actual procedure, like the best way to cut them off, best welding method....I have MIG welders....etc. getting ready to order everything to redo the undercarriage, just need to figure out which way to go on the sprockets Thanks Tom
Monkey....thats all well and good to get it off.....but it is so very important that it goes on correctly....there is a torque value...let me find the procedure an post it for you.....
I have had D21 dozers in my shop that have had three or four rims welded onto the same sprocket hub. As long as your hub is in good shape, you shouldn't have a problem. You could even weld new rims onto your hub without pressing the sprocket off.
well that was the plan Brad. It was an either, or thing....I was either going to pull the sprocket off and replace the whole sprocket, or just replace the rim. LOL, I wasn't planning on taking it off to replace the rim I kinda thought that was the main reason for just doing the weld-on rim, keep from having to pull the whole sprocket off Any issue or problem doing it while still mounted???
We haven't ran across any. I have never welded a rim on a D31P. All of the D31 dozers that I have seen have had a bolt on sprocket. The trick is getting it lined up correctly.
No problem doing it on the machine, just need to cut in the right spots. Grind everything good and clean, spot the new rim in place. Check it for trueness and get to welding. It shouldn't be a problem already being done once already. jr
Quicktrax......you still need to remove the sprocet....no?
We like to leave the sprockets on the machine. It keeps the price down and keeps our customers happy.
Hi QT, Maybe the Komatsu series 17 or 18 started using the bolt on type rims. My D31S-16 runs Berco weld on rims (KM391A) & Cat sealed links (688348X). Just wondered if you know what Cat machines use those same links.? My friend used to get his rims welded on his Cat 951C ,without removing them.I always wondered if all that heat caused problems for seals,etc ??? Jim
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undercarriage parts Hi,Jim,nice to meet you here,glad to know you are in need of undercarige parts,hope can be partners in the future.
Jim, Thats the same Berco# I looked up. KM391 is the weld on rim and KM390 is the complete press on sprocket. We have never had any problems with seals getting too hot. I have never had one leak that was caused by excessive heat from welding. I tried putting your link# into my system and it didn't come up as a good number. Check that # and make sure it is correct. I also tried 6S8348 and didn't get it to come up either. Thanks, Quick Trax
Hi QT, Each link has " CAT 6S8348X SEALED " on it. I assume it's an older chain with a new number. I wonder what Cat machines run the same pitch (154mm) ? Jim
Your link# is a 6s8343 and 6s8344. This is a D3B chain with the smaller diameter bushing (46.8). Your chain would also fit on a strait D3, D3B, D3C, D3G, 931, 931B, D4C, and the D4G. This is the older D3 chain. Your link height new was 84mm. If you ordered chains now you would get the updated chain which has a 6y0935 link#. your link height would be 88.mm and have a 50mm bushing. Both of these chains should have the 6.125 pitch. I hope this answers your question. Thanks, Quicktrax
Hi QT, That's the info I'm after. I spoke to 2 local Cat dealers & they gave me nothing! I assumed my chains would be from a D3/931,but didn't realise that the D4C had same links too.I assume this is the early D4C. I have some info saying the pitch on these Cat chains is 155.5. I suppose the extra 1.5mm isn't an issue,compared to the Komatsu pitch of 154mm. Thanks again, Jim
Jim, Your chains came off of a D3 or a D3B. Your link# wouldn't be on a D4C from the OEM. Even though your chains wouldn't have come on a D4C from the OEM, they will fit onto the machine without any problem. All of my aftermarket info says when selling new chains, upgrade to the 6Y0935 link# chain. The 1.5mm pitch difference shouldn't give you a problem on your Komatsu especially if the sprockets are a little worn. I just sold a set of used Komatsu D155 chains to a guy who put them on his D8K and he didn't have any problem. Their is only small insignificant changes that will not matter.
Thanks again QT, It's good to get advice from the guys who work this stuff every day. Some of the local salesmen might be better off selling tupperware... Jim
well started pulling the undercarriage apart. Quick thanks to QuickTrax for the great prices and service :notworthy Anyway got the shoes off, I'm thinking that was the easy part Since I have new chains, I'm guessing the quickest way to get the old ones off is just cut through a link with a torch ?? What do you guys do with the old chains....scrap yard After the chains are off, gonna tackle the carriers and rollers. Any good advice on getting the bolts out .....the head of the bolts are severely pitted/corroded. Looks like a socket may not even get a good grip on them. Don't really want to end up with a bunch of gnarled up bolt heads and end up torching them off and then try and drill out the rest of the bolt my new stuff
got the chains off, just cut them with a torch, and got all the rollers off. 3/4 impact wouldn't break loose a lot of the roller bolts, ended up having to heat the bolts up with a torch and then hitting them with the impact. Only had one twist the head off, after removing the roller though was able to put a stud remover on the exposed part and turn it out. All in all it wasn't to bad. Just waiting to find out more about the carrier rollers, seems to be some confusion at my Komatsu dealer
Monkey, The CARRIER ROLLER assembly number on the D31S-16 is: 113-30-00011 or 113-30-00010. I'm currently looking for Final Drive parts for my 16 series loader. PM me if you know of any being wrecked. Jim
thanks The parts guy is trying to find me an aftermarket assembly........not having much luck I'll look around for you
There are a few aftermarket makers of D31 undercarriage...Italian,Korean & Chinese.It shouldn't be hard to find a supplier,so maybe there are very few sitting in stock locally. Darin (on the Komatsu D21 topic) might be of help. Jim
yeah I got everything else aftermarket....just seems to be a problem with the carrier rollers. Trying to get the whole assembly that is a direct replacement seems to be the problem :beatsme