Scag hydro pumps and wheel motors

Discussion in 'Mechanic and Repair' started by A&P Lawn, Jan 18, 2009.

  1. A&P Lawn

    A&P Lawn LawnSite Member
    Messages: 6

    My Scag 61" STT has 2000 hours on it. I am experiencing lack of pulling power when climbing small hills. What is the lifespan of the hydraulic pumps and motors and what typically fails due to wear etc...? Also, I see a rebuild kit but does that replace the components that wear? Usually I do my own maintenance / repairs but haven't worked on the hydraulic components.

    Any help / suggestions appreciated.
  2. djagusch

    djagusch LawnSite Platinum Member
    from MN
    Messages: 4,350

    First off I would check the belt and spring tension to see if that is on the up and up. If that checks out ok I would ask a couple more questions. Since you do your own maintenance how often have you changed your hydro oil and filter? Is the oil look good? Any metal partials in the oil or does it have sparkles? Does the mower pull to one side or the other (is one side weaker)?

    If it doesn't pull to one side or the other I would suspect a belt spilling issue or possibly just overall wear to the system.

    If it does pull to one side then a component on that side is bad.

    If it is the overall wear or a pull to the side ask Restorob and the other guys on how to test out the components.
  3. A&P Lawn

    A&P Lawn LawnSite Member
    Messages: 6

    Belt and spring tension seems OK. First time I changed the hydraulic fluid and filter was about 600 hrs. Second time around 1400 hrs. Doesn't pull to one side or other just slows down. It doesn't prevent me from mowing, I just imagine it will get worse and during peak season, you know how it is trying to get anything repaired.

    Appreciate the info, will check with Restorob like you said.
  4. Gem Tang

    Gem Tang LawnSite Member
    Messages: 24

    I have around 6500 hours on my exmark hydros , it all depends on if you miss used the hydros by doing pop a weeles and donuts that does damage to the hydros to , check to see if the pumps are leaking anywear and if there is any kind of metal in the hydro oil stop and take it to a dealer if you don't know how to drain and flush hydro systems because you can mess your wheel motors up and have to replace them to good luck and have fun , and by the way they do sell all the parts in the hydro pumps indivendually
  5. A&P Lawn

    A&P Lawn LawnSite Member
    Messages: 6

    Thanks. That's encouraging if you have 6500 hours. Maybe I just need to change the fluid and filter again. Will give that a try.
  6. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Check all hose/line fittings for tightness, One could be sucking a little air but not bad enough to leak oil. Also make SURE the belt is good and tension is correct since both sides are acting up. The next step would be a pump flow test, A pump flow meter is a little pricey $3/400 for a one time use. Call around to your local shops and see if any have the tester to check the pumps for you.

    Good Luck
  7. A&P Lawn

    A&P Lawn LawnSite Member
    Messages: 6

    The tensioner isn't adjustable, it's a spring. I suppose it could be fatigued? Yeah, $3/400 would be a lot for once in awhile. I was thinking about ordering the rebuild kits and just going through them because of the hours as well but I suppose 2000 hours isn't alot right?? Basically trying to head off the problem prior to next season. Used to rebuild vein style power steering pumps and such but never worked on hydro wheel motors / pumps so didn't know if the rebuild kits replaced the common wear parts or just the seals and o-rings. I'm going to drain the system and look for metal particles. Refill and change the filter again. Definitely appreciate the help.

Share This Page