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  1. R

    Lost lift ability

    I bought a non working Lull 844C because the owner ran it too low hydraulic which can cause all kinds of problems. Destroyed the plastic seals in main pump then the parts jammed up relief valves. Required new pump and lots of tracing valves. These systems are self bleeding they work build...
  2. R

    Hydraulic hose for fork tilt

    Can't do it on the 10054 Skytrak idk others.
  3. R

    Lull 644B owners- Whats normal - whats not

    Is the 5060 what's spec'd for your machine ? I have seen some hackery with sun valves that fit and look identical to what's supposed to be in equipment but totally different valve messing up the functions. Here is the 4545B old one I replaced.
  4. R

    Lull 644B owners- Whats normal - whats not

    Ok
  5. R

    Lull 644B owners- Whats normal - whats not

    Yes usually off the shelf parts such as Sun valves but I found on my 844C some were proprietary made for Lull by various companies I think one was out if business. But these are common components for mechanical hydraulic systems and I am sure someone with knowledge could get a modern part in...
  6. R

    Lull 644B owners- Whats normal - whats not

    It's prob a Husco 4545B like in mine. But maybe the seal kit will work.
  7. R

    Lull 644B owners- Whats normal - whats not

    As long as it's a Husco 4545B it's the same but factory set pressures different for various applications Loosen locknut set pressure with hex key. Your pressures too low with relief valves. Bad O ring on valve can cause issue go to hydraulic seal supply or measure go to Hercules or rocket...
  8. R

    Lull 644B owners- Whats normal - whats not

    You need to start with a baseline take pressures on all here full Throttle and record. See what you are dealing with.
  9. R

    Lull 644B owners- Whats normal - whats not

    That needle inside relief valve was binding on mine I cleaned it up some with fine sandpaper. Be careful these are very expensive from JLG new $3500 and used from these scrappers like web equipment $1500 so don't lose parts or order when taking apart. I found and replaced mine with same models...
  10. R

    Lull 644B owners- Whats normal - whats not

    Tractormech Craig was the one that sent me that test procedure I posted. This shows relief valves you need to inspect.
  11. R

    Lull 644B owners- Whats normal - whats not

    There should be an adjustment test procedure for yours also.
  12. R

    Lull 644B owners- Whats normal - whats not

    I basically took out every valve in the valve block checked seals on them etc. A bad seal could cause problems also.
  13. R

    Lull 644B owners- Whats normal - whats not

    After I set my pressures with 2 relief valves my front forks would only go down not up. Took spool apart on valve block for forks cleaned it was fine after. You prob are losing pressure somewhere in system relief valve etc. Yours may have the mid inlet system which is different but this gives...
  14. R

    Lull 644B owners- Whats normal - whats not

    Here
  15. R

    Lull 644B owners- Whats normal - whats not

    Here
  16. R

    Lull 644B owners- Whats normal - whats not

    Your steering should be 2200 min. You shouldn't have pressure drops when activating functions. Here are some test procedures on mine 844-42C it's very similar to the 644 but yours may be different
  17. R

    Lull 644B owners- Whats normal - whats not

    my experience with hydraulics was working on sweepers that use 12v direction solenoids these Lulls are total mechanical systems and complex took me a good month or so to figure mine out. Just takes time and unfortunately very few know how to work on these tractor mech Craig helped me out a lot.
  18. R

    Lull 644B owners- Whats normal - whats not

    Yeah that's it.
  19. R

    Lull 644B owners- Whats normal - whats not

    Ok but you have a dual stage pump one could be fine other low pressure. On my tilt cylinders there is a 12v solenoid on the back cylinder that locks it when boom is out certain length via hall sensor signal. You can check if it's getting power 12v with a power probe. By default it's locked...
  20. R

    Lull 644B owners- Whats normal - whats not

    The system will have an idle pressure and max pressure when at high rpm's.
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