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Hydraulic lines in boom access

Discussion in 'Other Construction/Demolition Equipment' started by Ronray, Aug 29, 2018.

  1. Ronray

    Ronray Active Member

    Joined:
    Jul 6, 2018
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    Location:
    visalia
    I discovered blistering on the orange NC hydraulic lines inside the Boom about 20in back from the end of the Boom. Apparently the prior owner of this machine melted the lines during a welding repair. It's a marklift 62 ft straight 3 section boom man lift. I need to be able to pull the lines out enough to make the repair. I am not sure if I will be able to slide the lines out by extending the boom fully. I am using my tractor and a chain to pull the 20180714_184102.jpg 20180622_144403.jpg b oom fully out. I disconnected the holding valve and collecting the hydraulic oil from the cylinder as it squirts out. I'm just not sure if the boom will fall apart or be damaged if I completely extend it with my tractor. There is an inspection hole on the underside of the center boom section and it looks like the orange hydraulic lines are looped around. And I am not sure if I will kink them with the boom fully extended. Do the 3 piece booms have to be completely separated to replace the orange NC hydraulic lines?
     
  2. Ronray

    Ronray Active Member

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    Location:
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    I'm wondering if the two melted Orange hoses is just cosmetic with only the orange jacket being melted. I cannot pull the lines out for a closer inspection. If I plug the two hoses at the ends and pressure up the hoses is there some kind of device that will stop the hydraulic pump from overpressuring the lines and blow them out that way?
     
  3. Ronray

    Ronray Active Member

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    Location:
    visalia
    Well, I went ahead and pulled the boom out to maximum extension. When I looked under the inspection hole at the end of the first base section of the boom, the orange NC lines were still looped around. So I am assuming I cannot just pull the lines straight out from the end boom and that it would be necessary to disassemble all three boom sections? I also noticed a different date stamp on the orange line at the first base section boom than on the orange line in the third final section. So they must be connected together somewhere along the way inside the boom. So I'm thinking I may just see if it holds pressure with no leaks and leave everything as is and make sure I have a safety rope around my waist when I'm in the basket LOL
     
  4. mikebramel

    mikebramel Senior Member

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    Location:
    milwaukee
    AFAIK all man lifting devices will have have cartridges in the cylinder to lock the volume of fluid inside the cylinder. If the hose pops you will just loose motion and stay where you are at
     
  5. Ronray

    Ronray Active Member

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    Location:
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    Thanks Mike! So I am guessing the holding valve would do the same thing as that cartridge you mentioned? I did not see a cartridge in the cylinder that those orange lines went to.
     
  6. OFF

    OFF Senior Member

    Joined:
    Sep 30, 2009
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    Occupation:
    HD Mechanic/Shop Foreman
    Location:
    Alberta, Canada
    Ronray, I'm pretty sure that every lifting type cylinder on an aerial lift is protected by a holding valve. They don't want things to come crashing down should a hose fail. Under that plastic cover on your hoses is several layers of fiberglass wrap, protecting an inner rubber hose/liner. The plastic doesn't do much for the hose other than keep it clean. Do you know which functions those hoses operate? basket level and basket swivel maybe? If that pair of hoses is operating basket swivel, impact would minimal if the hose failed.
     
  7. Ronray

    Ronray Active Member

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    Jul 6, 2018
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    Location:
    visalia
    Wow, great advice. Thank you so much! Those lines operate the basket swivel, not the level, so now I feel better about trying it out.