9 March 2001


Save the frustration of a

mower that falls down on the

job when the grass is ready

for cutting with a pre-season

maintenance make-over,

suggests Peter Hill

FIRST, assemble some essential items: tool box full of spanners and wrenches, grease gun well charged with lubricant, operators manual, to find those out of sight, out of mind grease nipples.

Fully equipped, its time to tackle the mower after its winter lay-up.

Finding the operators manual is helpful because although mowers are generally pretty simple, straight-forward machines, it will provide a reminder of the essential maintenance points for the particular make and model involved.

The power take-off shaft is as good a place to start with the grease gun. But also check that the shaft telescopes easily to prevent excessive strain on the assembly and bearings as the mower is lifted and lowered at headlands.

Be sure, also, that the plastic guard is in good shape and properly secured (usually with a chain) to prevent it rotating with the shaft. This is, after all, an important safety feature, along with the cutting bed guards and skirts. These are the only things that come between toes and fast spinning blades and are designed to arrest stones and other debris before they can be flung through the tractors back window.

Drive belts, found mainly on mounted mowers, are best replaced if cracks or splits suggest they will fail during the season. Otherwise, simply check belt tension and adjust as necessary to avoid excessive slippage, wasted power and loss of cutting performance.

On drum mowers, be sure that the disc forming the base of each drum unit rotates freely – it helps the machine glide over the field surface. Similarly, check for wear on the fixed skid pads on disc cutting beds. These can be built up with hard-facing rods to give longer service before being replaced.

Moving blades from one drum or disc to a neighbouring one that rotates in the opposite direction will make use of the second cutting edge otherwise, it is better to replace worn blades with a new set at the start of the season rather than waiting until things get busy.

Where a conditioner is fitted, missing tines or flails need to be replaced – not only to ensure the device can work properly but also to avoid running the conditioning rotor shaft out of balance.

Drum and disc mowers need oil to lubricate drive shafts and gears. On drum designs (unless it is fully belt-driven) this is usually limited to a trough housing the shaft and bevel gears that transfer drive from the pto to each drum. Best to refer to the operators manual for guidance on fill level as this will vary from machine to machine.

With disc mowers, it is the cutting bed itself that needs a full supply of lubricant to keep the disc drive gears in good shape.

Checking the oil level differs from machine to machine. On some, it is best to have the bed level on the ground, with a welding rod or similar used to dip the oil through a fill plug on the upper surface of the bed. A 6mm fill is usually about right, though it is as well to check the operators manual for the correct figure.

On other designs, oil fill is measured with the bed upright at a plug typically about a third of the way up. It is usually a case of simply filling until the oil level reaches this point.

It is prudent to replenish disc mower beds with fresh oil every season given that replacing damaged cutting bed bearings can be a time-consuming task. The oil that comes out gives a good indication of the state of components hidden from view and, of course, fresh oil is simply a more effective lubricant.

Any movement of discs on the bed is an indication of bearing wear. This can result in expensive failure if ignored because debris can cause untold damage within the rest of the gear train. Better, then to replace worn assemblies before they fail.

Other things to check? The state of hoses and couplings if the mower has a hydraulic cylinder to fold it into its transport position, as well as wheel lift/lower cylinders, wheel nuts and tyre condition and pressures on trailed models.

The final task is to set-up the mower which, in the case of mounted machines, is best done on level concrete. The aim should be to adjust any suspension until the bed is lightly resting on the ground. Then, the tractors lift arms need to be set so that, when raised for a turn, the outer end of bed lifts clear first rather than being left behind to snag on a laid swath or some other obstruction.

With thanks to Paul Killen, agricultural engineer, Poughley, Berkshire.

Getting the mower into good shape well ahead of the grass cutting season can save headaches later.

Left: Protective skirts (as well as all other safety shields) should be in place and in good condition….

….likewise pto shaft guard tubes and cones (below).

Worn blades may only need reversing (which may mean moving them to a disc or drum with opposite rotation) to use the second cutting edge. Otherwise, replace with a new set and check for disc bearing wear at the same time.

Watch for leaking or damaged hydraulic hoses and pipes, and for damage to tyres on trailed machines.

Left: Protective skirts (as well as all other safety shields) should be in place and in good condition….

….likewise pto shaft guard tubes and cones (below).

Replace missing or damaged conditioner flails to maintain performance and avoid running an out of balance rotor.

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