1. Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

Kato HD 900 SEV slow operaion

Discussion in 'Excavators' started by Mark250, Mar 19, 2017 at 11:54 PM.

  1. Mark250

    Mark250 Senior Member

    Aug 30, 2015
    heavy equipment technician
    Hi all I need some help with a Kato HD 900SEV digger S/n 900514sw
    the machine has pilot operated controls for the main attachments and uses cables to operate the travel spools
    the problem is when machine warms up the functions on the left hand joystick go slow. operating the right hand joystick improves the slow functions. i suspect the pump signal system but do not know how it operates as the pilot lines go directly to the main control valve .there also appears to be no pilot pump as such.
    As I am unfamiliar with Kato hydraulic systems I am hoping some one on the forum can help with either experience or manuals and schematics
    Any help most appreciated
  2. Tones

    Tones Senior Member

    Mar 15, 2009
    land clearing contractor
    Queensland & Far Sth Coast NSW Australia
    There are 2 pumps piggy backed, each pump supplying 1 control bank.Follow the hoses from the pumps to find out what goes where.As a starting point flow and pressure test the pumps. If they are ok then move onto the control bank and test.The problem could be as simple as a broken 0 ring at worst a worn pump.
    Has this machine run a rockbreaker? If so check the quality of the hydraulic oil.I have experienced grease contaminated oil which came from using rockbreakers resulting in stuffed pumps
    Last edited: Mar 20, 2017 at 10:16 PM
  3. rocknrabbit

    rocknrabbit Member

    Feb 12, 2015
    vic australia
    I may have a manual to suit you, I will have a look for it when I hear from you. Where in this fair state of ours are you?