Schiller Grounds Care, Inc. - BOB-CAT® Full Size ZT Mowers: Power Unit – Underside Product Demo

BOB-CAT® Full Size ZT Mowers: Power Unit – Underside Intro

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BOB-CAT® Full Size ZT Mowers: Power Unit – Underside Belt

  • Remove PTO Idler Spring

    Remove the PTO idler spring.  A piece of starter rope works fine for this task.

  • Roll Belt Off Front Spindle Pulley

    Roll the belt off the front spindle pulley. 

  • Clutch Pigtail

    Take two flat blade screwdrivers and lift the tab on the clutch pigtail with one while using the other screwdriver to separate the plug halves.

  • Remove Bolts / Locknuts

    Take two ½" wrenches and remove the two bolts / locknuts that attach the clutch to the clutch stop.  Pull the clutch stop off its post after removing the two bolts. (It's fine to let it hang by the tie strap attaching it to the clutch pigtail.)

  • Take PTO Belt Off Clutch

    Take the PTO belt off the clutch.  Put a 3/8" ratchet extension into the pump idler arm to release the belt tension and drop the belt from the pump.

  • Install Pump Belt

    For installing the pump belt, it's easier to route the belt around all the pulleys but NOT the right-hand pump. Next attach the spring keeping a little tension on the belt by pulling it toward the right-hand pump pulley. Now use the 3/8" extension again to move the idler enough to roll the belt on the right-hand pump pulley. You can also route all the belts first and then try to put the spring on, but that's a bit harder.

  • Replace PTO Belt

    Put the PTO belt back on the clutch pulley, reattach the clutch stop and plug in the clutch pigtail.

  • Replace Belt

    Attach the PTO belt spring before you put the belt back on the front spindle pulley. Note the routing of the belt.

  • Final Belt Replacement

    Put the belt back into the groove of the center spindle pulley and roll it counter clockwise to finish installing it.


BOB-CAT® Full Size ZT Mowers: Power Unit – Underside Clutch

  • Remove PTO Idler Spring

    A piece of starter rope works fine for this task.

  • Remove PTO Belt

    Roll belt counter-clockwise off front spindle pulley.

  • Remove Pigtail From Clutch

    Take a flat blade screw driver and lift tab on plug to clutch and pull plug off clutch.

  • Remove Bolt

    Remove bolt retaining clutch and pull clutch off. If clutch is seized on crankshaft you will need to leave bolt loosely installed in crank to give puller something to push against. Another option to the puller is wedge something between clutch and frame so there is downward pressure on the clutch and use an air hammer on the loose bolt. This takes a little talent as the air hammer tends to walk off the bolt very easy. (A flat bit in the hammer works much better than a pointed bit.)

  • Reinstallation of the Clutch

    Installation is simply the reverse procedure with one very IMPORTANT
    Note; Crankshaft bolt MUST be torqued to 50ft lbs. Failure to do this WILL result in premature bearing failure (which is not warranty).

    Put a little “Anti-Seize” on the crank during reassembly to facilitate future removal. When correctly torqued to 50ft lbs the inner races will be held fast and not allowed to spin on the crank, thus ruining the crank.


BOB-CAT® Full Size ZT Mowers: Power Unit – Underside Engine-Pump Pulley

  • Remove Engine Pulley

    Follow instructions under “Clutch”. Pulley simply slides off after that step has been done.


BOB-CAT® Full Size ZT Mowers: Power Unit – Underside Idler

  • Remove Idler Pulley

    Put 3/8” ratchet extension into pump Idler Arm to release belt tension and drop belt from pump pulley.

    With belt off pulley, simply remove bolt. (the bolt is threaded into the idler arm so you don’t have to try to get a wrench on the topside of the pulley) It’s a good idea while you are under the unit, to hit the idler pivot with a grease gun if the machine is the older style that has a grease fitting.


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