steering "lock-up"

Discussion in 'eXmark' started by cutntrim, Jul 21, 2003.

  1. cutntrim

    cutntrim LawnSite Senior Member
    Messages: 474

    I've been having some steering difficulties with my Toro Z-150 and thought you might be able to help. I know, it's a Toro...but hey, Toro owns Exmark now right? The mower was purchased new in '99.

    Anyhow, the right steering arm will "lock-up" unpredictably while operating the machine causing a loss of steering which is somewhat disconcerting to say the least. It's happened while moving forward, and while moving in reverse, and while at top speed, or at slower speeds. If I'm on a wide open lawn I can bring the other (left) lever even with the right then 'toggle' the right to get it free. If I'm in a tight area, or a potentially dangerous area (i.e. slopeside, or roadside) I have to reach down and turn the key to kill the engine entirely.

    The service guy I use isn't a Toro or Exmark dealer. He's an independent shop owner. He figured it to be a pump problem and bled the pumps dry according to the manual, then refilled with Mobil 1. This didn't help. His brother works for a company called Parker which is a hydrolic pump manufacturer and he and an engineer from Parker disassembled the pump to have a look and could find nothing wrong. They all are puzzled, in that the problem is only on one side considering both pumps draw from the same resevoir.

    I'm wondering if it could be a steering linkage problem, rather than a pump problem. Do you have any suggestions for a problem of this nature?

    Thanks much.
  2. eXmark

    eXmark Manufacturer / Sponsor
    Messages: 4,258


    First let me say a qualified Toro dealer should inspect your mower ASAP. If the operation is as you have describe then your concerns are well founded.

    I'm going to assume that the Z-150 (I'm not totally familiar with their model system) is similar to our Lazer HP.

    If that is the case you have two pump, two wheel motors and one reservoir. The fluid is filtered after it leaves the reservoir before it splits to feed each pump. This prevents any contamination or debris from migrating from one side to the other.

    I'm not completely surprised that the pump checked out okay. I don't ever recall a pump demonstrating these types of symptoms before.

    I'd focus on the linkage, specifically ANY hardware that has ever been changed out for any reason. It sounds like something is binding up or your getting interference with the linkage somewhere. Look at the pivots, look for signs of ware. Any ware you find could indicate where youÂ’re getting metal to metal contact causing the binding or interference. One option is to remove the linkage from the pump or at the pump arm and then work the drive levers back and forth trying to make it bind.

    Again I am assuming this mower is similar to our Lazer HP. You should still take the unit into your Toro dealer. Safety first, production second. The lawns may be able to wait one day if it means getting the unit fixed right the first time or in this case the second time.


  3. cutntrim

    cutntrim LawnSite Senior Member
    Messages: 474


    I appreciate the reply. Yes, I think the Z-150 is comparable to the Exmark Lazer HP. Basically the exact same mower.

    I've forwarded your response to my mechanic and if he can't correct the problem I'll try the local Toro dealer.

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