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hydro pump problems

Discussion in 'Mechanic and Repair' started by Tim Louis, Dec 3, 2007.

  1. Tim Louis

    Tim Louis LawnSite Member
    Posts: 41

    While I was searching I noticed that someone touched on a problem I am having with my john deere hd 45 walk behind hydro pump. I read that normally the motor rotor, or pump rotor is usually wore along with the ball pistons. How do I tell that this is the problem with mine and how do I tell which one or if both needs replaced?
  2. Ironic

    Ironic LawnSite Senior Member
    Posts: 353

    I think for that you'd need to tear it apart and see.
  3. johnp900

    johnp900 LawnSite Member
    Posts: 71

    Have a flow test performed before you start tearing these apart
  4. Tim Louis

    Tim Louis LawnSite Member
    Posts: 41

    but what exactly am I looking for when it is tore apart? I have it tore apart.
  5. Ironic

    Ironic LawnSite Senior Member
    Posts: 353

    I think you'd need to find specs on the pieces, and then start measuring.
    but I've never had to do too much work on that type of motor, just seals
  6. bigmower1

    bigmower1 LawnSite Member
    Posts: 158

    im not sure which hydro pump model your talking about but most are all working on the same principle. First look at the ball pistons and none of them should stick at all, and on the back plate where they ride there should be no scortch marks. If there is a thrust bearing, it should look clean and the bearing case between the two rings should be in perfect shape. If there is any question about the shape of the thrust bearing, then just repkace it because that usually is the cause of hydro pump failure. If there is any metal or metal dust in the pump, then clean it out with kerosene and probably change the thrust washer assembly. some of them also have these plastic seals with an O ring,. they sometimes wear and when they do, your mower wont climb slight upgrades and the punps will vibrate and make a loud noise.

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