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Mechanics Corner: Maintenance and operator tips for mowers and mower-conditioners

Seth Doman Published on 06 May 2014

The first machines used in the preparation of hay and forage materials are mowers and mower-conditioners. Their proper maintenance and efficient use have a significant effect on the quality of hay for two reasons.

Clean cutting and optimum conditioning are, of course, critical, but perhaps equally important is having the machines ready on time and operating with minimum downtime when the weather is right to cut the crop at the its greatest nutritive value.



Many dealers who sell and service mowers and mower-conditioners offer scheduled maintenance inspections. This is a proactive way to be sure machines will operate at their best in demanding conditions and when you need them to.

These inspections include a visual and functional check-up of the mower or mower-conditioner and can be used either as a pre-season or post-season tune-up. Benefits include increased productivity, less downtime during the season, lower operating costs, improved fuel economy and improved machine trade value.

Since the machines are serviced by factory-trained service professionals, following the maintenance inspections regularly should result in a lower cost of ownership and higher resale values.

Regardless of these benefits, some owners will find it more convenient to make their own inspections. If so, here are some suggestions that should be helpful in making sure that all important points are covered.

Cutter bar components should be inspected on a regular basis to prevent expensive repairs and downtime:


Knives – for damage; broken, bent, missing or loose hardware

Lifters – for damage; bent, cracked and loose or missing hardware

Discs – for damage; bent, cracked and loose or missing hardware

Disc timing – discs should be 90 degrees to each other. (Discs that are not timed properly may indicate internal cutter bar damage.)

Starting at one end of the cutter bar, try to rock each disc up and down. A small amount of movement is normal. Excessive movement indicates a loose disc hub retaining bolt or worn top cap bearings.

Starting at the left end of the cutter bar and working down the cutter bar, grasp two adjacent discs and slowly rotate one disc while holding the other disc against the direction of rotation. If one disc suddenly moves, or excessive free play is felt, internal wear or damage is indicated.


Module lubrication is very important. Be sure to check the lubricant level of each module every 50 hours of operation. Re-fill with the recommended gear lube as needed.

In addition to prioritizing the time necessary to perform normal maintenance operations, using top-quality factory replacement parts and lubricants will go far in assuring that maintenance efforts will be rewarded with trouble-free and productive haymaking.

Proper set-up and operation are also very important. The tractor drawbar and PTO must be set up properly before attaching the unit to the tractor. If the tractor-to-mower-conditioner relationship is not properly adjusted, it will affect performance. Improper tractor hookup may result in PTO drive shaft failure, improper header flotation, incorrect cutter bar angle and poor crop feeding.

Adjust the tractor tread width so the wheels do not run over the windrow, if possible. Use a tractor with sufficient ground clearance to prevent crop from snagging and bunching on the underside of the tractor.

While operating, it is helpful to have the manufacturer’s trouble-shooting guidelines handy, so that problems in the field can be solved quickly. Examples are that excessive breaking or binding of knives and discs could be due to operating in severe, rough and stony conditions.

One solution is adjustment for lighter flotation. The tips of knives too far down could also be at fault, requiring adjustment of cutter bar tilt. Another culprit could be dull or missing knives, requiring replacement. Knives could also not be free to rotate.

If so, free them up. If the machine is leaving ragged stubble, it could be the result of improper PTO speed, and could be solved by adjusting PTO speed. Too-light header flotation could also be the cause; try readjusting to heavier flotation. Cutting the crop too high might also leave ragged stubble and can be corrected by increasing cutter bar angle.

Most operators are maintenance-conscious during the heavy use of the haying season. However, when the last crop is cut, equipment is often put away until next year with little thought to off-season storage and preventive measures. Refer to the machine’s operator’s manual for a complete list of storage procedures.

This information is being provided to help in operating and maintaining mowers and mower-conditioners with the final goal of producing the highest-quality hay and forage possible.

The machine’s owner’s manual should include most of this information and should always be the main resource for answers to machine operation questions. If the machine is operated by more than one person, be sure to share all information and helpful hints with everyone to maintain a top-efficiency operation. PD

Seth Doman is the Crop Preparation Marketing Manager for New Holland.