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Tracked Undercarriage, High Drive

Discussion in 'Dozers' started by John C., Aug 22, 2019.

  1. John C.

    John C. Senior Member

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    I finished the next video in the series about tracks and undercarriage. This time it's about the Caterpillar high drive and what to look for when inspecting it. Feel free to post comments and like the video if it provides some information that you could use in the future. A like on YouTube would be appreciated as well.

     
  2. Junkyard

    Junkyard Senior Member

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    I thought it was a good lesson in the high drives. Even as long as I’ve messed with them I had a couple aha moments.

    You have a new subscriber :)
     
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  3. Nige

    Nige Senior Member

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    There was obviously a lot of work went into producing that video. Well done.
     
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  4. John C.

    John C. Senior Member

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    Thanks Nige. It always means more from those who understand what they are seeing:)
     
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  5. DMiller

    DMiller Senior Member

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    I gained some new inspection insights when I go look for friends at sales. Nice video.
     
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  6. nicky 68a

    nicky 68a Senior Member

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    Thanks for posting John.
    I currently have rollers and idlers at 50%,grousers at 75%good,bushes at 80%worn,rail at 82%good and sprockets at 100%worn.
    Tractor is working in nice soft sandstone,but it's super abrasive.
    Previous D9T,D8L and 155's struggle to get 1500 hours on complete set.Turning has never been a successful story apparently.
    Machines were operated in 2nd cog.
    These days,I've got 1200 hours on general duty Cat chains before sticking £480 ITR segments and taking them on another 450 hours before selling that particular D8R.
    Cannon wear was still in spec and rollers were just starting to rub bushes,and I feel I would have achieved 1900 to 2000 hours.
    However,the D8T has the positive pin retention heavy duty chains with around 1200 hours in sandstone and 400 hours on general muck.
    The D8R and D8T are operated only in 1st gear and are treated very steady.
    I have Cat out frequently monitoring the tracks,and have been advised a turn is due now.
    I'm positive in my head,that the general duty Cat chains have given same bush wear as the positive pin chaines at a cost of £4000 less.
    Cat want £5200 to turn my ppr chains plus I'll have the cost of any hardware they don't reuse and the cost of transporting the track groups about the country to the track shop.
    The bill could easily be £6500 plus downtime.
    For reference,A brand new set of general duty Cat chaines are 9k(although they'll do them at 8k),a set of ppr chaines are 14k,a set of general ITM chaines are £5800 complete set and a set of ITR ppr chains are £7800 for the complete set.
    Million dollar question
     
  7. Nige

    Nige Senior Member

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    You are referring to the D8T I take it then Nicky..?
    Are the percentage you quote above "% worn" or "% of wear material remaining".? It's not 100% clear.

    If the numbers are % worn then my suggestion would be to stick another set of ITR sprocket segments on it and give it beans until the tracks reach the scrap limit. If at that point the grousers have more than 50% wear material left on them you could invest in a set of new chains and swap the existing shoes over to the new chains.

    I've never yet seen an operation where a pin & bush turn was justified financially. There may be some out there and I just have never worked on one, I dunno. We don't turn pins & bushes, we just run them until the tracks fall off.

    For mining (and also I would have thought anything larger than a D6) IMHO PPR chains are the only way to go and we never use aftermarket, they are cheap for a reason.
     
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  8. nicky 68a

    nicky 68a Senior Member

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    Yes,Nige D8T.
    My thoughts are to run them out.
    I've never had financial viability out of the ones I've turned in the past.
    As for ppr,I totally agree in D8 up in hard rock,but I've run general duty in this sand for years with no issues with pins migrating or breaking links.
    FYI....Segments 100% buggered,bushes 80% buggered but rails 82% good left.
    This tells me the the bushes are wearing much faster than the rails.
    The rest of the Cat undercarriage is wearing sound enough for my thoughts,it's just the ppr bushes wear out as fast as the general duty ones, therefore,I'm not getting any bonus or value out of the ppr chains (and they cost 4k more!).
    Don't get me wrong ,I've ripped with bigger tractors in granite and whinstone,and I believe the Cat undercarriage is the tool for the job
     
  9. nicky 68a

    nicky 68a Senior Member

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    When the time comes,I'll be buying a set of chains.I happen to have a brand new set of 24" Cat grousers in stock,so I'll simply buy some chains and fit the new pads at my leisure.
    As for the existing chains,the pads are currently around 70% good,so I reckon they would be around the 40%,left when my chains are eventually shot,so they will go back into the shed until I need to fit them on new chains again one day
     
  10. Nige

    Nige Senior Member

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    Only 18% wear on links if 82% left. Interesting. Are you sure the PSSR measured them right..?
    If correct, that little amount of wear on probably the most high-cost item in the tracks might just be enough to convince me to do a pin & bush turn. TBH I've never come across so little wear on links combined with so much on bushes. I wonder out loud if it is something to do with the interaction between the aftermarket sprocket segments and the Cat bushes.? Maybe my thoughts about another set of aftermarket segments are off the mark.?
    What's the track roller wear like.? Higher on 1/2 & 7/8 I imagine. Problem is with the arrangement of SF & DF rollers it's harder than it appears to swap rollers from the ends to the centre of the track frames.
     
  11. nicky 68a

    nicky 68a Senior Member

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    No Nige,the entire undercarriage on this D8 is all genuine Cat fitted at same time.
    As for the link height measurement being correct,the chap is an old timer that seems to know the score
     
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  12. nicky 68a

    nicky 68a Senior Member

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    Rollers are all around 50% give or take.
    Back idlers are actually 52%,worn and front 48%worn.
    I didn't get him to measure each roller this time as time was an issue on Friday,but Im not too far off the mark with 50% across the board
     
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  13. nicky 68a

    nicky 68a Senior Member

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    Slightly off topic,I run Cat cutting edges as they seem fair priced and wear well.
    However,the Cat general duty rip tip lasts longest,but costs far too much per hour.The John Moor tip has been. Cheapest in the trails per hour at £40.a tip,although MST is now supplying the tips at £90 but they last more than twice as long.
    Cat haven't a prayer on tips in our particular application.
    As for shank tectors,assume the ITR tector and Cat tector were absolutely free,the ITR tector pisses all over the Cat one.
    I have also pictorial measurements at various service intervals that show similar wear on the shanks themselves.....
    The Cat shank is £7000 although I payed £5800.The Italian CGR shanks made in China are £2200 .........
    I'm not suggesting the Cat tracks,shanks and tips are not the right deal for hard rock applications,but in the soft abrasive sandstone,they are more cost per hour than the cheapo stuff. I'm a massive Cat fan,but I'm struggling to be convinced that they aren't significantly more expensive to run per hour in the sandstone.
    I could be missing something here ,but........
     
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  14. Nige

    Nige Senior Member

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    For sandstone have you tried ARM-coated ripper tips..? A good option in relatively soft but abrasive material I would've thought.
     
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  15. nicky 68a

    nicky 68a Senior Member

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    Never heard of it????
     
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  16. John C.

    John C. Senior Member

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    Thanks for the insight nicky!

    I've experienced similar types of wear rates on tractors running in glacial till over laying sandstone. The high silica till, when wet, becomes lapping compound and takes out any sliding component wear right away. Sprocket segments and bushings on the reverse sides were maybe lasting 1,200 hours in the winters but the links, idlers and rollers running 2,500 or more. If we put the new undercarriage on in May, we could get to the middle of the following April. If we had to put the undercarriage on in November, we would be rolling chains on in June.

    When I was at the dealer, they got chains from the gold miners in Alaska all the time for a turn. All were D10 and 11 with PPR and all got wet turns. The chains had to be shipped down to Seattle and then shipped back up. I seem to recall the mine owners had their own supply barge which was running anyway but I could be wrong on that. Maybe running in sub zero weather made a difference in the way things got worn.

    One place I worked I put some IPD extended life chains on a D8H. The rails were twice as thick as found on any other brand of chain at that time. Instead of turning pins and bushings, I ran the first all the way through the bushings and then bought all new sealed pins and bushings and got the entire life of the rails. I don't think IPD is still in that business and it only worked for the D8 but in those days, I didn't find anything that worked any better.

    That D9H in the video is used for ripping and scraper operation and they are mixing and matching components from different tractors in order to maximize the wear life on all components. The chains on that machine came from a different machine that got all new. They were going to run the segments till you could shave and then throw some used ones on to run the rest of the undercarriage all the way out. I asked to use that machine for the video because it was a mixed bag like you might see at an auction or on a curb stoner's lot.

    Thank you both for the insight and your experiences.
     
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  17. nicky 68a

    nicky 68a Senior Member

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    Thanks for the insightful reply on the silica and on the unusual wear on the D9 John..
    Of interest,The track gent didn't fancy the idea of a system one undercarriage on the D8T for this application.He reckoned the wet sand grinds the seals out in no time~
     
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  18. nicky 68a

    nicky 68a Senior Member

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    After speaking with a mutual colleague on here,I've heard abit more on ARM GET products.
     
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  19. Nige

    Nige Senior Member

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    TBH I wouldn't consider SystemOne undercarriage on anything larger than a D6 and even then only if it was going to be in really light work. What you're doing ripping sandstone with that 8T cannot by any stretch of the imagination be considered "light work". I think it would tear SystemOne U/C to shreds.
     
    Last edited: Aug 28, 2019
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  20. John C.

    John C. Senior Member

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    So far most of what I have heard about System 1 is a mixed bag. Komatsu now uses the same track system and they call it Plus. I think a more descriptive name is parallel link, rotating bushing chain. The idlers on the Cat system ride on the bushings now instead of the links which might be a reason the seals show the short life. The Komatsu runs the links on the idlers.

    At least Komatsu puts a split link in their chains from the factory.
     
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