Lawn Tractor: Bad Vibration From Cutting Deck

Bearings are housed inside a stationary unit that allows the shaft to rotate within the housing. If a bearing becomes badly worn, it can cause vibration. To check the bearings for damage and wear, first remove your mower deck. Next, remove the mandrel covers and the belt, then spin all the pulleys and listen for a growling noise. If you hear anything odd, or notice excessive movement, you will need to replace the bearing in that unit. If you decide to change the bearings in the mandrel, first remove the blade, mandrel covers, and belt. Remove the bolt holding the mandrel pulley in place, and remove the pulley, collar, and dust cover. Once you have done this, the shaft will slide out. With the mandrel taken apart, you will need to tap the bearings out with a piece of wood or something similar that will not damage the bearings. Remove the bushing between the 2 bearings as well. If the mandrel has no grease fitting, be sure to pack the new bearings with grease. If the mandrel does have a grease fitting, then you will need to grease it after the bearings are installed. Tap one bearing into place and reinstall the bushing, then do the same with the other bearing. Re-install the shaft, dust cover, collar, pulley, and nut. Re-attach the blade, belt, and mandrel cover. With everything re-installed as it was before the repair, you can finally re-install the mower deck and your repair is complete.

If the belt is badly worn or has thinner parts in certain areas, it can cause the belt to jump and shake on the pulleys. To check the belt, you will first need to remove the mower deck, (refer to your instruction manual for this, as all models are different). With the deck removed, remove the mandrel covers and pull the belt off. Turn the belt inside out and check for signs of cracking, brittleness, grooves, and any other wear. If you discover any of these symptoms, you should replace the belt. With the new belt installed, you can now re-install the mandrel covers and mower deck.

The blades cut and mulch grass while your lawn tractor is operating. A bent blade will cause excessive vibrations. To check for a bent blade, remove the mower deck, turn it over, and examine the blades. With an excessive vibration, a bent blade should be noticeable. Replace the damaged blade by removing the hardware holding it in place, and attaching the new blade and tightening it down. Then simply re-install the mower deck.

The housing is a unit that contains multiple parts. If the mandrel housing is damaged in any way, you must replace the entire unit. Refer to our instructions for replacing the mandrel to complete this repair.

If a pulley is badly worn, it can cause a bad vibration from the cutting deck on your lawn tractor. To check all your pulleys, start by removing the mower deck. Next, remove the mandrel covers and belt, then check all the pulleys for play and roughness when spinning. Be sure to check the inside of the pulleys for wear, or any other signs of damage. If you notice any of these signs, you should replace the pulley. If you decide to the replace the pulley, first attach an open-end box wrench on the back side of the pulley bolt as you loosen the hold-down bolt. Now you can remove the old pulley and replace with a new one.

The shaft is located inside the mandrel and is supported by bearings at either end. Over time, the shaft can wear, and this can result in a bad vibration. To check for a damaged shaft, first remove the mower deck, then remove the mandrel covers and the belt. Spin the mandrels and listen for growling noises and check for any excessive movement. If you discover any of these symptoms, the shafts should be replaced. To replace the shaft, first remove the blade from the mandrel and unscrew the hold-down bolts. With the mandrel removed, disconnect the nut holding the pulley in place, and remove the pulley, the collar, and the dust cover. At this point, the shaft should pull right through. Replace with new shaft, reinstall the dust cover, collar, and pulley, and tighten the pulley back down. Re-install the mandrel back onto the mower deck and re-install the blade, belt and mandrel covers. Finally, you can re-attach the mower deck, and your repair will be complete.

The mandrel in your lawn tractor houses the bearings and shaft used to transmit power from one end to another. If the mandrel is badly worn, it can result in excessive vibration from the cutting deck. To check for excessive movement, start by removing your mower deck. Once removed, spin all the mandrels, and listen for growling noises, or excessive movement or play. If you discover any noticeable symptoms, you should replace the mandrel. If you need to replace the mandrel, first remove the cover over the pulley, and remove the belt and the blade under the mower deck. Then, remove the bolts holding the mandrel in place. Now install a new mandrel, and re-install the pulley, belt, and blade. Finally, re-install mower deck.