new hydro pump question

Discussion in 'Mechanic and Repair' started by vernon lawn, May 17, 2008.

  1. vernon lawn

    vernon lawn LawnSite Member
    from NJ
    Posts: 18

    I have a 2002 lazer z that had a pump go bad and with the high hours I decided to replace both pumps at once. Well since doing so I have one side only that is very weak and seems to go at half power. I'm not so sure it is air in the lines though. Any ideas?? Thanks
     
  2. 0526

    0526 LawnSite Member
    Posts: 10

    Make sure the linkage is hooked up correctly. There could be air in the line, but you usually hear a growling pump with air. Also, you will see foamy oil in the reservoir with air in the lines. If you do have air in the lines, check your pump case drain lines. They're the smaller lines connected with hoses with hose clamps over hose nipples. Use a screw type clamp to be sure these are not leaking air. They can leak air, but not oil sometimes.
     
  3. Breezmeister

    Breezmeister LawnSite Bronze Member
    Male, from South Jersey
    Posts: 1,569

    Is it the same side as the bad pump ?
     
    ericg likes this.
  4. White Gardens

    White Gardens LawnSite Fanatic
    Posts: 6,776

    Sounds like you got a bad pump. Did you evacuate all the air before you started the mower?

    I'd take it to a mechanic who can run a pressure test on the pump. It might still be under warranty too, so good luck.
     
  5. vernon lawn

    vernon lawn LawnSite Member
    from NJ
    Posts: 18

    It is the same side as the previous bad pump. I did my linkage adjustments and they are correct. A tiny bit of back turn in neutral position and it tracks straight. I did see some foamy oil so I'm going to check the return and filter lines again. Thanks for your reply's!!
     
  6. Breezmeister

    Breezmeister LawnSite Bronze Member
    Male, from South Jersey
    Posts: 1,569

    Seeing the foam maybe a good thing in your case, because the bad pump may have contaminated the oil and done damage to your wheel motor.
    Any way, here is a cross post from another thread from Restrorob.

    "Check all hose fittings for being tight, One could be sucking air but not bad enough to leak oil.
    Purge any air out of the system by jacking the drive wheels off the ground and block the unit. With the throttle set around 3/4 position slowly move the controls forward to reverse 8/10 times then test drive the unit."

    Good Luck
     
    ericg likes this.
  7. tomo

    tomo LawnSite Senior Member
    Posts: 660

    hello ,
    When u first started the system did u have the drive wheels elevated off the ground ? It is never a good idea to run a hydraulic system such as this under any load at all when started for the first time .This reduces the potential for the system to run dry and also bleeds any air out easily . Air locks would be rare but possible . More likely are damaged or faulty hose fittings letting in air .
    Is the hydraulic system two completely different curcuits/systems ??
    If the hydraulics are a combined system a complete dissassemly of all wheel motors and or pumps that were not replaced is recommended . [mainly to clean out any debris from the failed part]
    Optional is replacing the hoses as some metal particles can be embedded in the rubber .Upon start up they can dislodge and spread thru out the cleaned overhauled system and therefore cause more problems .

    The advantage to having seperate systems cannot be under estimated

    The first thing is to have the pumps checked at a hydraulic place, if they are not at fault the wheel motors are the culprit .

    Adjust al linkages to maker spec .

    tomo :waving:
     
  8. vernon lawn

    vernon lawn LawnSite Member
    from NJ
    Posts: 18

    Yes, I did have the mower up on stands and did the back and forth bleed out. Then I tested the unit and adjusted linkage as needed on ground. From there it seemed good for about and hour or so and then the power seemed to weaken on the one side. Next I think I'm going to go over all my inlet and outlet lines and re clean them and adjust the clamps for tightness. Should I re loosen and tighten all pressure fittings also from pump to drive? Thanks for everyones time in replying.
     

Share This Page