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Recoil Springs and Track Adjustment

Discussion in 'Dozers' started by kc5gxc, Jul 22, 2007.

  1. kc5gxc

    kc5gxc Well-Known Member

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    Howdy. I am wondering how important the track idler recoil springs are. I got one for each track, of course.....but does one really need 'em? It's easy to get slack by using other methods. Is all this spring stuff necessary?
    As long as one has the cylinder working to apply tension to the track, if the spring breaks or the brackets breaks, would one replace it for any reason?
    Just looking at them and seems like a lot of machinery (the springs and brackets, etc....) for nothing!!!!!!
    Thanks, Pete
     
  2. Jeff D.

    Jeff D. Senior Member

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    Pete, the way I understand it, those springs are there to prevent the track from getting too tight and breaking something or (over time) wearing out the bearings. The track will get tighter when dirt, rocks, snow, etc, build up in the undercarriage & sprockets during operation.

    The slack that's in the tracks when they're clean is the most slack they'll have, but they do get tighter during operation sometimes.

    I really noticed this while plowing snow with mine. The springs became compressed almost fully.:confused:

    If it were me, I'd leave them in, or replace them if they're broken. Busting a final drive could get real spendy.

    Good luck.:)

    Jeff
     
    Last edited: Jul 22, 2007
  3. Wulf

    Wulf Senior Member

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    Yes, I think you need them...

    Hi Pete,

    The recoil springs are really shock absorbers to protect the undercarriage and the final drives from overload. When you are travelling the machine and the front of the track comes across some resistance the idler will move back and compress the spring. If the spring wasn't there it would cause a shock to the frame, the tensioner piston and the drive train depending on what type of crawler it is.

    Also... you adjust the track with the machine parked, the tension will change when working and the undercarriage gets packed with soil, mud or even snow. The recoil spring will compress to relieve the pressure on the sprockets and the track bushings protecting the link assemblies and the final drives from damage.
     
  4. kc5gxc

    kc5gxc Well-Known Member

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    Thanks for the information, guys.
    I looked at those springs and the mountings, and it's hard to see just how they work....was thinking all they did was get slack in the track when you let grease pressure off.
    Both of mine are broken towards the rear. Been that way a long time. Don't guess one could weld them to repair???
    Thanks again.
    Pete
     
  5. Wulf

    Wulf Senior Member

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    *danger*

    The springs are already under compression when installed on the machine, there is a high potential for injury if they let go either during repair or disassembly.
    What machine is it and what exactly is wrong with the springs?
     
  6. DPete

    DPete Senior Member

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    I had to put springs in one side of a D8K, there are two, inner and outer, both were broken and allowed the track to slack when turning enough to skip a bushing. They are very important to protect final drives also.Like Wulf said they are dangerous to work on. I had mine done at the Cat dealer.DP
     
    Last edited: Jul 23, 2007
  7. LowBoy

    LowBoy Senior Member

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    "Spendy"...I like that. Gots a real ring to it. Now alls I gotta do is SPLAIN it to my wife...:scool
     
    Last edited by a moderator: Jul 23, 2007
  8. radd16

    radd16 Active Member

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    springs

    you don't really want to mess those springs unless you have the right tools to take them apart. I pulled some out of a d65 komatsu took it over to the track shop to replace the seals inside, when they started to take it apart the nut had so much rust that it came apart uninspectedly and shot through a big roll up door.
     
  9. kc5gxc

    kc5gxc Well-Known Member

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    I did some studying of them springs today. Think I understand how they work now. Both of mine are broken towards the back, first or second ring of the spring. They are still in compression, however. Tapping them with a hammer tells that. This is a Komatsu D21P-6.
    Just put a new carrier roller on the left side. Ran the heck out of it today and did some ripping and tearing. Clearing land and making burn piles.
    Had a big pile and a 10" dia pine tree laid on it that fell down between the blade and radiator when I shoved the bottom of the pile.....I hate that...ha ha. I almost had to go get the chainsaw to get that thing off , but finally found a cut off tree that I could pick up and pry it off with. It was a persistant tree that just wanted to go with me...ha ha ha.
    Thanks for all the good advice.
    Pete in MS
     
  10. surfer-joe

    surfer-joe Senior Member

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    First thing you do with a busted recoil spring is either reach in thru the top opening if there is room, or cut a new one in the roller frame with an acetylene torch and cut the busted spring -- carefully -- into at least two maybe more pieces to relieve the tension. You will probably have to cut the retainer rod apart too. Mud and rust and the constant hammering tends to weld them together to the point a big rattle gun won't move the nut. Never try to retrieve a busted recoil spring without doing this, they'll kill you given half a chance.
     
  11. Dozer575

    Dozer575 Banned

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    I know of someone that got killed at a dealer, when I was a high schooler.
    D8 recoil spring. If I remember it put a good hole in the wall too.
     
  12. kc5gxc

    kc5gxc Well-Known Member

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    Well, the springs are broken on both sides of this Komatsu....toward the rear.
    They still have tension on them (both). The guy I bought it from said they had been broken for a long time, and no ill effects had been observed from it. I guess they are still serving their purpose, all seems ok with the tracks. Do people replace them in this condition or run 'em like this if they still have tension?
    I also see a track roller on left rear getting sloppy. Think I gotta take of the guard to replace it. The bolts/nuts are in rough shape, but easy to get to. Think just one side of guard off should get me to the roller to remove. (komatsu D21P-6)
    Thanks, Pete
     
  13. Dozer575

    Dozer575 Banned

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    As long as you just power in the forward direction you will be okay. The time it is noticable is when backing up a steep hill, or such things as stump splitting. The only thing that may be of concern is what else is being damaged if the spring is not seatting in the correct way. Extra slop in the tracks will make things wear faster.
     
  14. kc5gxc

    kc5gxc Well-Known Member

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    Thanks for the info Dozer.....I'll keep an eye on them...all still working ok far as I can tell....tracks stay at tension....springs no slack even with breaks. Hope I don't have to mess with 'em. The old dozer runs mighty good.
    Pete