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Bobcat Hydraulic Problem

Discussion in 'Truck & Equipment Repair' started by Weld&Fab, Feb 24, 2009.

  1. Weld&Fab

    Weld&Fab Junior Member
    Messages: 2

    The center curl cylinder came apart on my Bobcat 743. I have never repaired a cylinder before but when I took the cylinder off of the machine and pulled the ram all of the way out and saw the last thread pulled off I was fairly sure of what happened. I took it apart, repaired the threads and re-assembled it. I put the cylinder back on and it works fine. The problem is now the control valves are noisy and the fluid looks a lot lighter. Could I have air in the system? How do I get the air out? I plan to drain the fluid and change the filter… should this take care of it?
  2. keitha

    keitha Senior Member
    Messages: 133

    You will have some air in there, any signs of damage/
    metal hamburg in the cylinder when you opened it up?
    Change the oil & filter asap. The lighter color could be foaming
    from the air. A milky color indicates water contamination.
    To bled cycle the bucket several (a bunch of) times.
    Use good quality oil and filters and you'll be good to go.
  3. Weld&Fab

    Weld&Fab Junior Member
    Messages: 2

    Thanks for the reply.........
    There wasn't any sign of damage or debris in the cylinder. It looks like the nut on the end of the ram had worked its way off until it finally pulled the last thread on the nut and the ram. I put a heavy chamfer on the nut to remove the bad thread and re-chased the thread on the ram to clean up the end. I made sure the cylinder was clean inside and out and the seals looked good. I have the fluid draining now but it is moving like molasses in this cold weather. The Bobcat manual say to use their oil or 10W 30. I have been using 10W30. I wonder if their oil is lighter and would be better in the winter?
  4. mrfixitpaul

    mrfixitpaul Junior Member
    Messages: 11

    The Bobcat oil has extra additives to protect the hydrostatic pumps that 10-30 doesn't. It's probably cheap insurance to use their oil. Sometimes the oil needs to get hot before the air all works out...1/2 hr. or more of working machine should do it.