Over time all riding mowers including those in the John Deere line will eventually need some attention paid to the hard-working underside of the equipment. Knowing the parts and functions of the components that make up the mower deck, from belts to blades and bearings, will help you maintain and if needed make the proper repairs to keep your lawn maintenance schedule on track.
The John Deere engine drives the mower deck belt directly. The belt, in turn, drives the pulleys to rotate the cutting blades. Mower deck belts require replacement about every two cutting seasons. With prolonged use the belt tends to stretch and become brittle from the heat generated during normal operation.
The groove of the pulley can be bent or damaged during deck installation or removal. Pulleys mounted on the spindles fit directly to the spindle shaft. A bolt and washer retains the pulley in place. Idler pulleys incorporate press-fit bearings in their center; these bearings mount to a stationary shaft and maintain belt tension and alignment.
There are different types of blades; mulching, bagging and standard cutting blades are the most common. While all blade types cut grass equally, they each process the cuttings in different ways. For example, mulching blades continuously chop up the grass cuttings after the initial cut for improved mulch. However, they do not perform exceptionally well when they are used with a bagger attachment. The selection, quality and sharpness of the blades is crucial to mower deck performance.
Bearings play an integral role on a mower deck, maintaining shaft alignment in the spindles and reducing friction. Bearings perform a similar purpose on the deck’s idler pulleys. Bearings experience almost as much punishment as the mower blades. Aside from the blades and belt, they are usually the first parts to wear out on a mower deck.
There is a spindle for each cutting blade mounted through the mower deck that transmits mechanical energy from a motor-driven belt directly to the cutting blades. The top of the spindles supports a belt pulley. The bottom of the spindle attaches to the cutting blade. Spindles install as an assembly, with the exception of the blade and pulley.