Rating undercarriage wear?

tjdub · Jul 26, 2010

Is there a specific formula for measuring undercarriage wear, or is it just an educated guess? Most dozers that I see for sale will have a percentage listed, but I don't know where they get number from.

Anonymous-0 · Jul 26, 2010

Most of the time people are guessing. Usually to their benefit. There hoping the buyer doesn't know any better. The only way to know the actual wear left is by carefully measuring and comparing to new specs. This is expressed in a percentage of wear left, ie/ 60% undercarriage or as, how much it has worn, ie/ 40% worn. The first example is the most common method. Dave

Flurette Farm · Jul 26, 2010

135, is right. there is of course a mechanical way through measurement that is generally unused. All guesses will be in the sellers favor. Be very cautious.................

Lou from Wi. · Jul 26, 2010

Dave hit the nail on the head. Undercarrage can not be determined by what the seller says. SO BEWARE of so called percentages left. LOU

MSM · Jul 26, 2010

There is no specific formula for wear. Each machine has its own set of specs. The bushing diameter is measured,pin to pin length is measured,roller and idle diameters are measured,rail height is measured. Once this is done these measurements are compared to the manufacturers specs and a percentage figure is arrived upon. A blanket 60% undercarriage statement can be very misleading. The chains could 70% worn while the rollers could only be 10% worn,and the sprockets could be almost new.
Since the undercarriage on a small dozer can easily cost $6-8000+ or a larger dozer or loader $12-20,000to completely replace or rebuild it would be money well spent to have a track shop check the undercarriage before purchasing a tractor

RodinNS · Jul 26, 2010

Wear is properly expressed as a percentage of the difference between new specs and maximum wear specs... which will be somewhat different for every machine.
More often that not this is someone's best guess... although Cat generally will send a service rep out to measure an undercarriadge 'here' at no cost. I don't keep in touch with them as much today as I used to when we worked our machine more... but at that time they did those measurements yearly for us simply as customer support...

I doubt that you will find too many machines today that won't eat 20 grand on a full carriadge overhaul IF you're using SALT chain along with quality components like Cat or Berco.

Rod

dpendzic · Jul 26, 2010

go to crawler heaven web page for wear limits on various machines
http://www.nnalert.com/

Anonymous-0 · Jul 26, 2010

I looked at a used Cat at Finning. They listed percent of undercarriage left for each of the sperate components. Rails, bushings, bottom rollers, top carrier rollers, idlers, sprockets and pads. They usually don't all wear at the same rate. Dave

tjdub · Jul 27, 2010

Thanks, those charts look very useful.

Charles Irland · Jul 27, 2010

Four good "HINTS" are. 1) look at the front of the track frame. If the end of the Idler Bracket is getting to within an inch or two of the end its time to turn/replace the pins & bushings. 2)Look at the "pin boss'" this is the raised area on each link that the pin goes through. when you look at them where they are close to the bottom rollers the flanges of the bottom rollers SHOULD NOT cover any part of it if the bottom roller flange is half way up the pin this is a good indication that the undercarage will need extensive repairs. 3) Block up the drawbar and use down pressure with the blade to lift the tractor off the ground. Reach down and grasp each bottom roller and try to move it if you feal ANY movement other than smooooth rolling it will soon be time for expensive repairs. 4) Reach in to the inside of the chain and feal for a deep dent where the sprocket comes in contact with the sprocket, the deeper the dent the more life is gone from the chain.

These hints should help you at least let the seller know you have done some homework and they usualy will be more forthcoming with some of the crawlers quirks.

gary in canada · Jul 30, 2010

looked at the chart and im a little confused (sometimes happens easy,lol)it shows that a d8h as over 36 inches across 4 links, i think thats wrong , doesnt a d8h have an 8 inch pitch x 4 would be 32 inches

730d se · Jul 31, 2010

All of this is great information and what some sellers do not want you to know or want to discuss. I even see ads where the seller says "good undercarriage". I can only imagine how much time he spend measuring everything to come up with that result. LOL
Keep in mind the use of the crawler. If you are going to put it in service, you want everything measured and know where your "hours remaining" are. However, if it is going to be a trailer queen, or just run occasionally, you can be a little less demanding. Chances are you will wear out before the U/C needs much replaced, as long as you keep the adjustments checked and proper lube.

Rating undercarriage wear?

tjdub

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Anonymous-0

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Flurette Farm

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Lou from Wi.

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MSM

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RodinNS

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dpendzic

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Anonymous-0

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tjdub

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Charles Irland

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gary in canada

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730d se

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