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JLG 450 Series II boom lift - any wrenches here?

Discussion in 'Other Construction/Demolition Equipment' started by John Canfield, Nov 4, 2019.

  1. John Canfield

    John Canfield Well-Known Member

    Joined:
    Apr 27, 2009
    Messages:
    237
    Location:
    Texas
    My JLG 450 Series II articulated lift all of a sudden lost its full speed capability. Even in rabbit mode it will not go faster than a normal walk speed. The out of level light does work and the creep light will come on when out of level. Speed and boom controls do slow down when out of level then speed up a little but not much.

    Any ideas?
     
  2. Mikefromcny

    Mikefromcny Well-Known Member

    Joined:
    Nov 12, 2009
    Messages:
    180
    Occupation:
    Mechanic
    Location:
    Upstate NY
    Is your lower boom stack down all the way? Check for a stuck switch where your upper boom meets the tower.
     
    John Canfield likes this.
  3. John Canfield

    John Canfield Well-Known Member

    Joined:
    Apr 27, 2009
    Messages:
    237
    Location:
    Texas
    I do believe the lower stack was fully lowered but that's a good tip about checking switches, thanks Mike, really appreciate the help.
     
  4. John Canfield

    John Canfield Well-Known Member

    Joined:
    Apr 27, 2009
    Messages:
    237
    Location:
    Texas
    Beautiful day here so I took a look at the boom for a switch that might be not be operating properly. I found one on the inboard side of the main boom, when the boom lifts the switch either goes open or closed. The switch has a roller on the end of a lever that either contacts a cam or doesn't. Also found one old bird nest and under the boom end in the cavern an angled plate that must have been lost from a previous repair job (along with one bolt.) JLG450Switch.jpg JLG450SwitchOverview.jpg JLG450MysteryBracket.jpg
     
  5. John Canfield

    John Canfield Well-Known Member

    Joined:
    Apr 27, 2009
    Messages:
    237
    Location:
    Texas
    "Even a blind chicken finds a piece of corn once in a while..."

    I sprayed the two switches (one at each pin end on tower and mast) with Deoxit and moved the switch plungers several time. And we're back to normal operation, yippee! Either I fixed the problem or this was just an amazing coincidence that it started working.

    The problem wasn't intermittent so I'm fairly confident I've isolated the problem, if it happens again I'll replace both switches.