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941 Bottom Rollers Rebuilds?

Discussion in 'Track Loaders' started by Metalman 55, Nov 14, 2018.

  1. Metalman 55

    Metalman 55 Senior Member

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    Got a few leaking bottom rollers on the old 941 that I want to rebuild if it is feasible...…….good idea to try?

    I will definitely not buy new cat rollers for a machine that hardly gets used, but would like to try the rebuild option on one or two to start with to see how it works. There are about 5 to do in total. Are they likely to need both bushings & seals? I just wanted to try to be somewhat prepared before yanking out a roller...….. I have a parts book, but never having seen a roller apart before, it all looks greek to me...……...
     

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  2. Nige

    Nige Senior Member

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  3. Metalman 55

    Metalman 55 Senior Member

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    Ok, thanks. We ordered both the Duo-Cone seals, the Toric rings & a retainer clip, enough to do one roller & go from there after we see if it is successful. The shells look ok, externally at least, so if the bushings are still good we will leave them to be reused. BTW are the cap bolts that hold the rollers on coarse or fine thread? I wonder how they will come off? Note on the one pic, the one bolt is broken off. I did spend some time yesterday reviewing the 955 roller rebuilding that you had mentioned from a couple of years ago. It was helpful.
     
  4. Nige

    Nige Senior Member

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    A couple of thoughts.
    A complete Duo-Cone Seal assembly includes two silicone rubber Toric Rings. You don't have to buy them separately unless you plan on just replacing them rather than the complete D-C assembly.

    The bolts that secure the end caps are 3/8" coarse thread I think. Post your Serial Number and I'll sort some parts listings out for both double & single flanged rollers. These will work so long as you don't have aftermarket rollers installed (look for the Cat logo cast into the end caps).
     
  5. Metalman 55

    Metalman 55 Senior Member

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    Ser # is 80H2988 on the 941.

    The seal kit ordered is both the Duo-Cone seals & the Toric Rings, if we understood it correctly. The part # for what we ordered is #
    9W5224 which we understand to be the whole group. Hope we have that right.

    I was referring to the bolts that secure the rollers to the track frame (4 bolts) & wondered if they were coarse of fine. I believe they will be 3/4" diam.
     
  6. Nige

    Nige Senior Member

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    The Duo-Cone Seal Group for your track rollers is listed as a 2M-2858 which upgrades to 9W-5224, so it appears that you have the correct P/N.
    Attached the parts listings for both single and double-flanged rollers.
    The bolts that secure the rollers to the track frame are actually 5/8" coarse thread.
    Do you have access to the necessary 224-9466 tool to install the Duo-Conde seals..?
     

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    Last edited: Nov 14, 2018
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  7. Metalman 55

    Metalman 55 Senior Member

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    No, we were going to try it without. Can we do it without one if we are careful?

    Do you remember if the 955 man that rebuilt his rollers used the tool or not? I could always look back in the post to see if he mentions it.

    Thanks for the helpful pdf files as well!
     
  8. Nige

    Nige Senior Member

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    You can do it without, it's just that the tool makes it a lot easier. On a really big seal it would be pretty much impossible without the correct tool.
    It helps to understand how the seal works, and why everything must be 100% oil-free for the installation.
    In the diagram below the Toric ring #2 is jammed between the ramp #7 and the corresponding ramp in the housing (not shown). When the ring #1 is pressed down the Toric Ring rotates in an anti-clockwise direction and becomes "the spring". If the Toric Ring is allowed to slide on one or both of the ramps it will not function as a spring and the seal will most probably leak.

    upload_2018-11-14_21-57-42.png

    The #1 mistake that is made installing Duo-Cone seals is that it's a pretty tight fit to force the Toric Ring past the Lip #8 on both sides. The first thing that folks do is to grab some lubricant to help the process, but if you want the seal to work right after installation that's the last thing anyone should be doing.
     
    Last edited: Nov 14, 2018
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  9. Theweldor

    Theweldor Senior Member

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    I have done it with out the tool. It is alot easier with it though. But can be done without. Be very careful as all of the corners are very sharp on the steel rings. You can end up with many cuts just like a paper cut in a heartbeat.
     
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  10. Dave Neubert

    Dave Neubert Senior Member

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    10-4 on the cut hands I never had the luxury of a seal tool I always use a blunt screw driver but do not roll the o ring in you have to push it in as you hold pressure on the metal seal and yes always install dry and make sure the part where the o ring goes is cleaned up good
     
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  11. Welder Dave

    Welder Dave Senior Member

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    It was a long time ago but don't the rollers have to be put in a press to separate them? I remember in school I went for work experience at a heavy equipment repair shop and spent a day pressing rollers apart with a horizontal press designed for it. I'd guess it was a 75 ton or larger press. When pressing they would start going tick, tick, tick and then a big bang when they finally came loose. You could see the pressure build on the gauge. I think you had to turn one of the mounting flanges 90 deg's in order for them to come apart. I think it was so the shells could be rebuilt on automatic equipment or just new shells installed. The shop had 2 idler rebuilding machines that used to run 24/7 back in the day. I also remember having to cut a hole in the side plate on hollow idlers so the heat from welding wouldn't build pressure inside. After they were built up, you'd weld the circle back in. It was easy to tell if the idlers were ever rebuilt because they'd show the patch welded back on.

    http://www.maruma.jp/pdt_r_ip.html
     
  12. Metalman 55

    Metalman 55 Senior Member

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    Got one roller off the machine & got the two retaining rings off & one collar off, but the other one is giving trouble......seems seized to the shaft. Any tricks to getting it off? We positioned in in a press just to hold it steady for us to work on. On the one end that we were able to get apart, it looks like the duo-Cone seals may be good, but will have a better idea once they are cleaned up. Just doing one roller at a time to see how it goes, as winter is setting in here & don't want to have too much apart at one time.
     

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  13. Nige

    Nige Senior Member

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    Does this help at all..?
    Probably a lot of penetrating oil (and a fair amount of patience while it soaks in) required......
    https://www.heavyequipmentforums.co...help-on-tensioners-and-injectors.40068/page-6
     
    Last edited: Nov 15, 2018
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  14. Metalman 55

    Metalman 55 Senior Member

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    Good idea! I guess I missed that when I read that guys post from the other night, but that makes sense for sure. I do have a heavy vise too! Stay tuned...……….
     
  15. Nige

    Nige Senior Member

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    No use re-inventing the wheel.
    I'm sure the end caps are well rusted in place. The two P's spring to mind - Penetrating oil & Patience.
     
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  16. Metalman 55

    Metalman 55 Senior Member

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    Success!! The vise, penetrating oil, two adjustable & a few taps on the one side with a 2lb hammer & it got things moving. Thanks for the tip!:)
     

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  17. Metalman 55

    Metalman 55 Senior Member

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    Ok.....now I get it, once it is apart & cleaned up. The rubber ring needs to twist up the ramp in order to hold tension against the metal mating Duo-Cone seals, thus the need to be dry. If they were lubed they would slide & not have the intended effect.

    BTW the old Duo-Cone seals on the first roller taken apart are about 1/2 the thickness of the new ones but they look good...…...reuse them, only changing the Toric Rings & keep the new ones for the next roller if it is worn worse?
     

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  18. Nige

    Nige Senior Member

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    How does the width measurement of the wear surface of a new seal compare with the one you removed..? That's the shiny bit in your photo above.

    upload_2018-11-16_16-5-29.png
     
  19. Metalman 55

    Metalman 55 Senior Member

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    Mating surface width on the new one as shown in your sketch is approx. 1/8" & old one is about double that at 1/4".
     
  20. Nige

    Nige Senior Member

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    How wide is the face in total on your seals..?
    Is the wear surface still pretty smooth or is is grooved from dirt getting into it..?
    upload_2018-11-16_19-20-46.png
     
    Last edited: Nov 16, 2018