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Hydraulic cylinder piston nut keeper

Discussion in 'Other Construction/Demolition Equipment' started by Ronray, Jul 14, 2018.

  1. Ronray

    Ronray Well-Known Member

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    20180713_175338.jpg Any suggestion on what to do with this little punched hole to stop the nut from coming loose? I was thinking of possibly trying to just pry the edge up out of the way from the nut and hoping it would not break when I press it back down after replacing the nut. I'm guessing that Loctite on the nut might not hold up inside a hydraulic cylinder?
     
  2. funwithfuel

    funwithfuel Senior Member

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    Just back that nut off. It'll restore the threads. When you got it off, file those threads down a hair. It'll be fine. Don't dimple in the same place. That's asking for a flake to cause you further grief. Good luck
     
  3. Ronray

    Ronray Well-Known Member

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    Thanks! Does it take any kind of special hardened punch to make a new dimple? Or should my Harbor Freight punches do the trick? And maybe I could experiment by attempting to Dimple in the middle of the piston rod?
     
  4. funwithfuel

    funwithfuel Senior Member

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    The threaded end should be just plain old steel. I don't know if HF punches will do the job . I know snap on and craftsman punches will. All you're doing is creating an interference fit so that the nut cannot back off. Personally, I like to ding the nut . When you torque her down smack it again on an angle in toward the threads. Locked up tighter 'n dicks hat band.
     
  5. thepumpguysc

    thepumpguysc Senior Member

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    YUP.. just unscrewing the nut will be fine..
    Use some Loctite on the threads when you reassemble it & tighten the sh*t outa it..
    The torque on some of them are upwards to 600 ftlbs.. 300 is the "norm" tho I think..
    THATS WHY someone "staked" it.. probably didn't have a TW that went that hi.??
     
  6. John C.

    John C. Senior Member

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    What kind of machine and what function is the cylinder used for?

    Staking a nut does virtually nothing to hold the nut from coming loose. I usually take a die grinder to the part sticking out the farthest to keep any damage to the nut to a minimum.

    Find out a manufacturer's torque specification if possible when reinstalling. If not available then consider the amount of pressure used to operate that particular function against the size of the nut. I'm guessing from the photo it is around 2 1/4 inch or larger and 600 to 1,000 foot pounds would be more in the range for a system operating in the range of 3,000 to 5,000 PSI hydraulic pressure. Locktite 262 would be my preferred liquid to hold the nut.
     
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  7. Ronray

    Ronray Well-Known Member

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    The nut takes a socket 1 and 7/8 inches. The cylinder is the basket leveling cylinder at the end of the final boom on a marklift 62 aerial lift. I just got a large set of impact sockets to fit it, but not sure if my half inch air impact driver will have enough torque. I was unable to crack the nut with a 3-foot breaker bar
     
  8. Ronsii

    Ronsii Senior Member

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    Doubtful a 1/2 inch impact will work.... get a 8 foot pipe for your breaker bar, if the 1/2 inch drive holds up it might work... you'll probably need a little bigger tooling or at least a pretty large pipe wrench and extension pipe.
     
  9. tool_king

    tool_king Senior Member

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    Half inch drive is not going to cut it .You will need 3/4 or 1 inch drive to get it off and retorque it back on to spec .
     
  10. John C.

    John C. Senior Member

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    Take it to a cylinder shop with a bench. They can break it loose and tell you the torque. Better yet have them repack it while you are there.
     
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  11. Ronsii

    Ronsii Senior Member

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    Some very good advice there :)


    Unless you are really wanting to save a few bucks and your time is worth next to nothing ;) a shop can do a cylinder like that in less than a couple hours... full service.(provided they aren't backlogged a week or two)

    Among some other benefits of a shop set up for these things, they can also hone and polish the can and rod while fixing any other issues that may be in there to make sure it lasts a long time.

    They can also do a proper pressure test to make sure it is safe and 100 percent ready to do it's job :)

    There is a lot to be said for having the right tools for the job, makes it nearly impossible to cause more damage to the cylinder wile trying to work on it... of course if you have some decent fab skills and are willing to do a bit of research it really isn't that hard to make any tools you will need ;)

    And most shops I have used in the past use good parts from reputable suppliers for the seals,wipers and other wearable parts... not some odd ball import funky rubber that leaks two months after you install the cylinder...

    Anyways it really isn't that hard to work on these things... BUT you really need to know what you are doing before you start... there is lots of info around for those that wish to DIY it but remember it isn't something that everyone can do the proper way....
     
  12. thepumpguysc

    thepumpguysc Senior Member

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    I give you a pat on the back for making it THIS FAR..
    Theres "normally" 3-4 PAGES of people asking HOW TO get the cyl. off & HOW TO get the gland nut off & WHERE to buy the tool..
    I did have to chuckle a little, when you said you tried a 3ft breaker bar tho..
    You came on here w/ a decent question & a very clear picture for your [almost] 1st post.. {hell} I cant even do that..Lol
    BTW> some of those threads are "backwards", so watch out for that.. good luck.
     
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  13. Ronray

    Ronray Well-Known Member

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    thanks for all this great info! Yep the threads are normal not backwards. Also my half inch air impact did not have the torque so I'm going to be picking up a 1-inch impactor tomorrow. I couldn't even get the wheel lug nuts off with my half inch air impact, so I know that all of these heavy-duty tools will be getting put to use. And I will be taking all of these disassembled parts to a really reputable hydraulic shop locally. I did not see the Loctite 262 on my Loctite list, so I guess I will just Google it or see if this local hydraulic shop has it. Does that Loctite 262 have to be heated in order to remove it, in case I have to remove that lock nut again?
     
  14. hvy 1ton

    hvy 1ton Senior Member

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    272 is for 3/4-1 1/2" thread fasteners.
     
  15. thepumpguysc

    thepumpguysc Senior Member

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    Not to hijack the thread but.. I've always gone by the color when using Loctite & never bothered to learn the #'s..The #'s in my experience, kept changing for the same thing.. So I just kept up w/ the colors.
    Blue is> service removable.. the "fastener" is held in place, but if it has to be removed again, it can be, with some force.
    Red is> "in-there" & cant be removed without a small torch..
    Green is> Permanent.. used for loose bearing races, bushings & such..
    Then theres another "thick" Red, used on the threads of oil/fuel line fittings when screwed into aluminum..
    Not to be confused w/ White pipe dope thread sealer..
    I think they{Loctite} tag it as, "Hydro. thread sealer"..
    Whenever ANYBODY asks me about WHAT Loctite to use.. I always say, "A COLOR".. & 99% of the time its BLUE..
    BUT.. in this instance I'd have to say, RED.. its gonna be a cold day in hell when someone has to get back in there.. & given the amount of torque that needs to be applied to the nut.. if you miss the mark, you def. want something holding it/ helping it..
    Good luck w/ the repair..
     
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  16. Ronray

    Ronray Well-Known Member

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    Wow, great information. So just curious would that color scheme apply to other brands of threadlocker besides Loctite?
     
  17. Ronray

    Ronray Well-Known Member

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    What about using Loctite on hydraulic line connectors like to the holding valve in this picture? I actually discovered that this threaded nut was loose and only held on by a couple of threads and it was leaking oil, and the location of this holding valve was on the aerial lift basket leveling cylinder which was set inside the final boom and set back a good 12 to 18 in from the end of the Boom thereby making it really difficult to see and reach. If you would use Loctite on those threads, which color would you go with? Just w ondering if you had to use the red and a torch to get it off if that heat from the torch would damage the holding valve?
    20180718_025748.jpg
     
  18. thepumpguysc

    thepumpguysc Senior Member

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    I cant speak for other manuf. as I've only used Loctite.{color}
    Check one of the fittings.. they might have an oring or nylon insert on the nut.. if so, I prob. wouldn't use anything on them.
    You'll be able to tell once you remove it, if anything had been used on the threads..
     
  19. kshansen

    kshansen Senior Member

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    Those look like JIC/SAE fittings should not need any thread locker on them.

    Now if you have one of those that has some minor damage and is seeping oil there are copper gaskets available that can solve that problem. Kind of hard to find but I know Cat for one does sell them if you can find a parts guy who knows where to look up the numbers.

    Usually the best fix would be to replace the fitting and line but sometimes that is not as easy as one would like!

    Edit: Took a bit of searching but finally found the information on the copper seals for JIC fittings!

    Copper Seals for JIC Fittings.png

    Did anyone else know that there was a torque spec' for a hose fitting?
     
    Last edited: Jul 18, 2018
  20. Ronray

    Ronray Well-Known Member

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    Wow this is great to know. But my fitting was leaking simply because it was loose. I just purchased this used aerial lift, so I assume the nut either came loose on its own or the prior owner's mechanic forgot to tighten it down or something. I would not normally put threadlocker on a hydraulic fitting like this, but since this fitting was in such a remote hard-to-reach location, that's why I was thinking thread lock.