No power to hydro

Discussion in 'Mechanic and Repair' started by joee0914, Oct 2, 2013.

  1. joee0914

    joee0914 LawnSite Member
    Messages: 126

    About two days ago the lower O-rings on my hydros were replaced. The bolt had stripped out which held the plate on causing it to leak pretty bad. I decided after re-tapping the bolt hole that I'd replace the O-rings on both sides.


    Number 132 in the picture.

    Once apart I allowed both hydros to drain very well since it was getting close to oil change time anyway. Once all put together and o-rings replaced, I refilled the system with oil, once it would not take anymore oil, I opened the bypass valves and ran the levers in forward and reverse a couple of times to purge the air. After that I closed the valves and jacked up the mower and did the same thing to push any remaining air out.

    Once I tried to use the mower it sounded like there was still air in the system. It had no power and made a loud screech.

    I tried purging any other air out but it seems like the system is completely purged.

    I jacked the mower up one last time to make sure I wasn't leaking or had something incorrectly installed but everything seemed fine. I decided to take the cover, where the o-rings were replaced, off again just to make sure it all looked good and once everything was put back together it seemed to cure one side but not the other.

    Any ideas on what may be the problem or did I maybe miss something.

    Sorry for the long drawn out description, figured it might help.

    Also Hydros are - HydroGear ZT2800
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Try purging with the bypass valves closed as follows;

    Raise and block the drive wheels off the ground. Start the engine and run about 3/4 throttle, Move the controls full forward then full reverse slowly 8 to 10 times, Then re-check fluid level and test drive.....
  3. joee0914

    joee0914 LawnSite Member
    Messages: 126

    I did this when purging the first time around... No luck

    I purged air by:
    1 - Open bypass valves and move motion control levers slowly forward and reverse about 6-7 times
    2 - Closed bypass valves and jack up drive wheels of mower and move motion control levers slowly forward and back about 6-7 times
    3 - With drive wheels still off ground, ran mower with wheels at full forward speed for about 10 Minutes.
  4. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    I've serviced 6 of those ZT2800's this summer with only one problem, which I'll describe secondarily.

    This may seem like a redundant question at this point but did you remove the vent plug when you refilled the transmissions? If not, you may have some trapped air space in the unit. Did the transmission accept the approximate 77+ oz.(about 2.5 quarts) or twice that amount if both were serviced?

    When I serviced the transmissions, I had the Zturn rear wheels about 4" off the floor for draining and refill with the vent plugs removed. I experienced no problems whatsoever. Once refilled, the unit was started and the handles
    moved both forward and reverse without a hint of hesitation. Just my observations.

    The only problem I had on the first unit was with the filters. With no Hydrogear replacement filters within 25 miles, I attempted to use Wix's crossover recommendation and that was not a good choice. Filter threads were correct but the diameter of the filter was sufficiently larger to not seal properly and the filter shields would not reattach without shimming--don't go down that road,:hammerhead:

    Just a couple of thoughts.
  5. joee0914

    joee0914 LawnSite Member
    Messages: 126

    I attempted to locate the vent plugs but what I thought were the vent plugs didn't seem to have a way to remove them.. They looked as though they just had a 1/8th inch wide hole in the center... Are they meant to just pop out or am I looking at the wrong thing?... I believe what I'm looking at is number 11 in the above diagram.
    Posted via Mobile Device
  6. Jeff in AL

    Jeff in AL LawnSite Senior Member
    from Alabama
    Messages: 789

    The Charge Pump Cover is directional and sounds like it is on backwards...

    If the Charge Pump Cover is aluminum it shouls be replaced with a 4th updated version which is cast iron and will not warp and allow the o-ring to leak.

    See if your reference number 203 is/was part number 71411 which was the last upgrade until the cast iron cover which is part number 72274.

    Attached Files:

  7. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    Joe, the vent plug, #11, is removed with an allen wrench/bit. I removed them with a 1/4" drive allen socket--can't remember whether it was metric or standard.
  8. herler

    herler LawnSite Fanatic
    Messages: 5,139

    I have a similar problem on a Lesco 52", air in the units, I can get power to the wheels but not full on.
    Parker motors, maybe I'll start another thread.
  9. billc1004

    billc1004 LawnSite Member
    Messages: 138

    jeff in al .. might be right plates to in one direction
  10. aroddy

    aroddy LawnSite Senior Member
    Messages: 397

    I had this exact same problem on a ZT3100. and just like Jeff in AL said. I had it on backwards when I put it on. I called hydrogear and the lady told me first thing try to switch it, she saids it happends all the time. Switched it around and it went to normal.

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