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Air in Hydro system?

Discussion in 'Mechanic and Repair' started by Grasscape Inc, Sep 7, 2010.

  1. Grasscape Inc

    Grasscape Inc LawnSite Member
    Posts: 235

    Just had the Hydro pumps and wheel motors changed....Makes some different noises than before..How do I know if there is air in the system?

    Exmark hydro gear pumps w/ parker wheel motors.
    Not the newer unitized system.
    Exmark hydro oil/filter
  2. Machinemonkey

    Machinemonkey LawnSite Member
    Posts: 8

    If the oil in the reservoir is frothy or yellowish color there's air in the system. your hydro oil should be a clear dark consistent color.
  3. timberattler

    timberattler LawnSite Member
    Posts: 7

    If you do see the frothy oil, the way to purge air from the system as follows.

    Park mower on level surface and use floor jack and board to jack both back wheels off the ground.

    Loosen both hex heads on the pumps like you would to tow the mower.

    Crank it up and run the steering levers forwards and backwards for 10 minutes or so at full throttle.

    This should purge the air from the system.

    Don't forget to re-tighten the hex heads on the pumps!

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