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undercarriage ??'s for D31

monkey

Well-Known Member
Joined
Aug 4, 2010
Messages
136
Location
lousyana
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
 

JimInOz

Senior Member
Joined
Apr 15, 2008
Messages
508
Location
Victoria, Australia
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
 

Leroy

New Member
Joined
Sep 2, 2010
Messages
1
Location
Illinois
Occupation
Retired
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
 

monkey

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Joined
Aug 4, 2010
Messages
136
Location
lousyana
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
 

monkey

Well-Known Member
Joined
Aug 4, 2010
Messages
136
Location
lousyana
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
 

MrKomatsu

Senior Member
Joined
Jun 12, 2009
Messages
437
Location
Houston Tx.
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.....
 

QuickTrax

Senior Member
Joined
May 27, 2009
Messages
368
Location
Houston
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.
 

monkey

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Joined
Aug 4, 2010
Messages
136
Location
lousyana
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 :confused:

Any issue or problem doing it while still mounted???
 

QuickTrax

Senior Member
Joined
May 27, 2009
Messages
368
Location
Houston
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.
 

jrtraderny

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Joined
Nov 26, 2006
Messages
236
Location
New York
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 :confused:

Any issue or problem doing it while still mounted???

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
 

JimInOz

Senior Member
Joined
Apr 15, 2008
Messages
508
Location
Victoria, Australia
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
 

ALLPOWERANGEL

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Sep 7, 2010
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Location
Fujian China
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sales of uncarriage parts
undercarriage parts

It is my great honor to be here to discuss with all you guys about the technology about UC parts,I am a seller,don't know much about technology.hehe~~~~\\

Hope can learn more here

Best wishes!
Angel Zheng
ALLPOWER MACHINERY
Tel:+ 86/591/87433773
Fax:+ 86 /591 /87433785
Website: www.allpower-machinery.com
MSN: angel@allpower-machinery.com
Skype: allpower.angel
Cell: 86-15205018921
Add: 2701#,Xinhuaxing Plaza ,NO.155. Hualin Road, Fuzhou,Fujian, China.
 

ALLPOWERANGEL

New Member
Joined
Sep 7, 2010
Messages
2
Location
Fujian China
Occupation
sales of uncarriage parts
undercarriage parts

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

Hi,Jim,nice to meet you here,glad to know you are in need of undercarige parts,hope can be partners in the future.
 

QuickTrax

Senior Member
Joined
May 27, 2009
Messages
368
Location
Houston
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
 

JimInOz

Senior Member
Joined
Apr 15, 2008
Messages
508
Location
Victoria, Australia
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
 

QuickTrax

Senior Member
Joined
May 27, 2009
Messages
368
Location
Houston
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
 

JimInOz

Senior Member
Joined
Apr 15, 2008
Messages
508
Location
Victoria, Australia
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
 

QuickTrax

Senior Member
Joined
May 27, 2009
Messages
368
Location
Houston
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.
 
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