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Komatsu wa400-5L hydro's

Discussion in 'Wheel Loaders' started by grf_1000, Apr 30, 2019.

  1. grf_1000

    grf_1000 Member

    Joined:
    Nov 30, 2016
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    Location:
    michigan
    I had an employee blow a hydro line, ran it pretty low on oil before shutting it down. After replacing line and refilling, the main pump was a little noisy. So I replaced with a new remanufactured Komatsu pump. Now I have no reaction on the lift or bucket. No reaction on steering either. Now before the line blew, it had a slight leak from a seal dumping into the transmission (like most of the machines develop). When bleeding the air out, the main bleeds fine. the steering/lift side is aerated quite bad. Pump shaft seal was replaced but still dumping into the trans.
    I've had a mobile truck service guy working in this and he is at a stand still for finding the problem. Hydro tank was drained and nothing abnormal came out. No excessive metal or anything. This was a cab off pump change.
    Anyone with any ideas that is familiar with these machines?
    any pointers would be greatly appreciated.
    Thans
     
  2. John C.

    John C. Senior Member

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    Did you replace the suction side hoses and all the O rings on the connections to the pump. I'm pretty sure there is also more than one pump on that machine.
     
    Vetech63 likes this.
  3. grf_1000

    grf_1000 Member

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    Hoses were goid, o rings were replaced. You are correct it does have more then one pump, the main pump was replaced. The shaft seal was replaced on the steering/ lift pump, which is the the that is aerating when trying to bleed. What's a couple pounds of air pressure gets oil to it with no problem but when it's running aerated when trying to bleed it.
     
  4. Wytruckwrench

    Wytruckwrench Senior Member

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    Wyoming
    If you are getting air it has to be coming from the suction side someplace. Suction side hoses would be a good start. Sometimes reusing the hoses they will have a “set” to them where the clamps have been or a clamp will been covering a pin hole.
     
    Vetech63 likes this.
  5. DK88

    DK88 Senior Member

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    Jan 19, 2011
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    Occupation:
    Field service tech.
    Location:
    Ontario
    switch pump failed, possibly coupling depending on arrangement.
     
  6. grf_1000

    grf_1000 Member

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    Nov 30, 2016
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    Location:
    michigan
    it's been a while. Thought I'd update.
    Took the switch pump off and had a shop check it out. Was told it had some wear but should have operated. So I have a new oem spec pump being delivered this week.
    The two things that get me are.
    1. the loader worked before the pump change(cab off). Hydro's just slowed down after it warmed up.
    now it has no lift or curl on the bucket, also no forward or reverse.
    2. It is filling the trans from the hydro tank in a matter of minutes.
     
  7. grf_1000

    grf_1000 Member

    Joined:
    Nov 30, 2016
    Messages:
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    Location:
    michigan
    Question could the reman oem main pump be put together wrong? Sucking instead of pushing?
    fins in backwards?