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undercarriage work

K

ktm250rider

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Jul 10, 2010
Messages
157
Location
canterbury nh
I knew it was coming. I found a broken tip on one of my drive sprockets. The teeth were worn to a point when I bought the machine but the price was right. The machine has about 8500 hrs and the bushings seem to be worn as well. Cant gage the idler wheel for wear, it looks pretty good to me. The shoes are in good condition. Could I just replace the drive sprockets and not worry about the other undercarriage components? Im using the machine around the house so I wont be putting many hours on it, while i own it. I dont have a price on the bushings but the sprocket and idler wheel are about $1100 per side.
 
xcmark

xcmark

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Feb 28, 2010
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357
Location
Foxboro , Ma.
Occupation
construction
If your only looking to get a 100 hours out of the bottom end and resell it maybe see if there is any used parts around. Changeing the entire under carrage on a high our machine is going to get very expensive !
 
captain charlie

captain charlie

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Oct 10, 2009
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88
Location
Sunshine Coast BC Can
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Home Trade Mstr
You might want to take it to a welder and have him build up the broken tip and add more weld to other tips and reshape them. Good time to check the idlers and rollers for wear and tear.
 
JDOFMEMI

JDOFMEMI

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Jan 3, 2007
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SoCal
What size machine are you talking about?

The answer may be different depending on whether you are talking about a 3 ton mini, a 45 ton machine, or, more likely, something in between.
 
JDOFMEMI

JDOFMEMI

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Look into an aftermarket sprocket. Berco may be helpful to you. If it was a production machine, it would be different, but for home use, the cheaper parts would do fine for you.

Any pictures?
 
K

ktm250rider

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Jul 10, 2010
Messages
157
Location
canterbury nh
The sprocket is actually the cheap part. I can get a pair 400 bucks. Its the idler wheel thats 900 per side and Im not sure what the bushings would be. I got pics somewhere, ill try to get them up.
 
JDOFMEMI

JDOFMEMI

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I have rarely seen a problem with idlers on an excavator. They dont travel enough to wear out like a dozer. I have seen them crack due to the constant impact in rough digging. I just weld them and keep going. If it wears out, the flange will get thin, and then it will crack at the edge of the center hump.

With excavators, the main problem is the pin wear inside the bushings. This is due mainly to flexing over the ground. The bushings rarely wear out on the outside before the internal pins have wore to the breaking point.

I have ran many machines with the sprockets looking pretty bad. Depends on what you do with it how big of a deal it is. Mine mainly load trucks on relatively smooth ground, only climbing to get on a bench. Then I pull with the stick to help.

If you do any work on a slope, it is much more important to keep it in good shape.
 
DirtHauler

DirtHauler

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Joined
Nov 25, 2007
Messages
507
Location
Seattle WA
Occupation
Heavy Highway Dirt Hauler
ktm250rider said:
Im using the machine around the house so I wont be putting many hours on it, while i own it.
Click to expand...

I would not worry about it if that is all your doing. One broken tip on a tooth in your situation does not justify replaceing it. BUT do keep an extra close eye on the sproket and if you notice it acting any differently now than it did before then that changes things.
 
thebaz

thebaz

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Joined
Nov 25, 2008
Messages
251
Location
Australia
The thing to check is whether the pins are worn to the point where the bushes are out of pitch with the sprocket, as this will cause the bush to ride up to the tip of the sprocket and then compress the spring on the track adjuster till it releases with a bang. This is possibly what broke the tip off the tooth in the first place. If this is the case new sprockets will not help much. If the sprocket is not skipping or slipping when you travel you may get your 100 hrs without having to do anything.
 
RonG

RonG

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Dec 2, 2003
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1,833
Location
Meriden ct
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heavy equipment operator
ktm250rider said:
I knew it was coming. I found a broken tip on one of my drive sprockets. The teeth were worn to a point when I bought the machine but the price was right. The machine has about 8500 hrs and the bushings seem to be worn as well. Cant gage the idler wheel for wear, it looks pretty good to me. The shoes are in good condition. Could I just replace the drive sprockets and not worry about the other undercarriage components? Im using the machine around the house so I wont be putting many hours on it, while i own it. I dont have a price on the bushings but the sprocket and idler wheel are about $1100 per side.
Click to expand...

One of my brothers lives in Canterbury,he used to own Merrimac Sheet Metal until he retired.Ron G
 
K

ktm250rider

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Joined
Jul 10, 2010
Messages
157
Location
canterbury nh
thebaz said:
The thing to check is whether the pins are worn to the point where the bushes are out of pitch with the sprocket, as this will cause the bush to ride up to the tip of the sprocket and then compress the spring on the track adjuster till it releases with a bang. This is possibly what broke the tip off the tooth in the first place. If this is the case new sprockets will not help much. If the sprocket is not skipping or slipping when you travel you may get your 100 hrs without having to do anything.
Click to expand...

Uh ohh, this is what may be happening, I need to verify. Crap, I really didnt want to have to replace the bushings. May be a winter job. PUll the track into the basement and go to work.
 
Q

QuickTrax

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May 27, 2009
Messages
368
Location
Houston
ktm250rider,
The easiest way to check if your pins and bushings are wore out is to look at the brackets on your idlers. If they are sticking out of the roller frames means they have a lot of wear and you don't have long until you start breaking pins. If they are not out of the frames and your sprockets are not jumping over you should keep running the machine. Once your sprockets start jumping over I would put new sprockets on it and go until the pins and bushings are junk. At that point I would go to your local track shop and get new pins and bushings installed into your chains and put new sprockets on again. At the time that you need to do something about your pins and bushings, check the new chain price also to see which one is cheaper. This is how you would get the most bang for your buck.
Good luck,
Quicktrax
 
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H

Hanomag

Member
Joined
Aug 8, 2009
Messages
23
Location
SW England
The easiest way to extend the life of the tracks is to remove one complete link from each track (your machines front idlers are probably hanging off the end of the track frames). Just cut out one link, you might need to weld the track pins in. If you are only going run a hundred hours a year the above will work.
If you decide to re-track the machine buy complete chains as the old track links will not take new bushes (the bores in the links will be stretched because of the hours and the wide excavator shoes). Get as much life as you can out of the old tracks before spending money on new.

Regards
 
K

ktm250rider

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Joined
Jul 10, 2010
Messages
157
Location
canterbury nh
Is it possible to replace the bushings myself? What tools are needed, can I just drive them out. I think i need a parts break down on the machine.
It looks like the bushings are junk. Some are actully worn right through so I can see the pin on the inside.
 
thebaz

thebaz

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Nov 25, 2008
Messages
251
Location
Australia
There is pretty much no way you can do pins and bushings without the special track press and then you would have to know how to use it. These pins and bushes are pushed in with hundreds of tons of force so it is both difficult and potentially dangerous. Once the bushes are worn through to the pins, you reduce the chance of successful pin and bush replacement and replacing the whole chain is often more economical and a better option in the long run.
The only cheep way out is to get used parts that are still serviceable. Unless your idler and rollers have unserviceable bearings, you can generally still get away with using them if they are worn, as a good chain will still travel reasonably true and not come off too easily, however an undercarriage is only as strong as it's weakest link and any worn part will cause a problem. Since you are only going to do a small amount of hours you will have to at least start with the chains and sprockets and see how you go.
 
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Q

QuickTrax

Senior Member
Joined
May 27, 2009
Messages
368
Location
Houston
You would need a track press. I have never heard of someone replacing the pins and bushings without a track press. Even though your bushings are worn to the pin, you could still install new pins and bushings into your links. We have three track presses and we do it all the time. You could find your closest track shop and see if they have someone who could look at your machine. Most shops will send someone out at no charge hoping to get the work. Your machine takes the same chain as the CAT 312. This is a very common chain so aftermarket parts should be readily available. Be sure to check the price of a new chain vs. pins and bushings. I believe a new aftermarket chain should run around $1150-$1200.
Good luck,
Quicktrax
 
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