1 March 2002


A PROGRAMME of thorough pre-season service checks helps to avoid time-consuming breakdowns later in the year. Such advice applies particularly to harvesting machinery, including balers, where delays due to poor reliability can cause expensive crop losses.

We asked Paul Muskett, a harvest product specialist with CNH Global, to demonstrate the round baler checks he recommends before the season starts. Mr Muskett chose a New Holland 658 baler fitted with a Cropcutter pre-chopping rotor, but most of the points covered in his pre-season check apply to other makes and models.

Factors affecting safety are given high priority in Mr Musketts baler checking routine, with the first item on the list being the drive shaft from the tractor pto. The guards should be checked for damage, all chains should be operating, and the universal joints should be examined for signs of excessive wear.

Drive shaft

The drive shaft examination should check for lubrication between the inner and outer sections, allowing them to slide easily and vary the length of the shaft as the tractor and baler are working. If lack of lubrication or damage to one of the shaft sections hinders the sliding action, the wide angle joints are exposed to extra wear and increased risk of failure.

This is also the appropriate time to check the drawbar pin. At the end of the harvest the baler pin may have been borrowed for another machine, so make sure it is replaced by a suitable pin before the season starts again. If the pin is too slim for the ball joint in the baler drawbar it will allow too much movement when starting and stopping, damaging the ball joint.

The safety latch on the pin should also be checked, and make sure the drawbar ball joint is lubricated and moves freely. The balers road lights also feature in the safety checks and should all be in working order.

The next area on Mr Musketts checklist includes the drives to the rollers and belts. The NH658 has four slip clutches and, as on most modern balers, these are all sealed units. Checking that the clutches are correctly set is a job for the local dealer with special equipment, but the on-the-farm checks should include greasing the clutches – but dont be over-generous with the grease gun, he warned. Large amounts of excess grease can find their way into the clutches and, particularly with the two rattle clutches, the lubricating action of the grease would interfere with the clutch settings.

The heavy duty drive chains on many modern balers, including the NH658, should have a long and virtually trouble-free life, but it is still important to check the chains and the sprockets for wear. On older balers with lower specification drive systems, the examination should be more thorough and will include checking the sideways flexing in the chains.

"For older New Holland balers we offer a winter service kit consisting of five replacement drive chains and about seven sprockets," says Mr Muskett. "This replaces most of the drive mechanism and it is ideal if you have an old baler to refurbish or to do up a second-hand machine. Fitting the new drive components is not difficult and can be done in a reasonably equipped workshop."

Automatic lubrication systems are used for the drive chains on many round balers, including the NH658, and the system should be covered in the pre-season checks. Oil is delivered to the chains through plastic tubes and a small amount is delivered each time the tailgate opens.

To check the system, pull the chain end of each tube in turn from its oiling point and check that an oil drop is produced when the tailgate is opened and closed two or three times. Reasons for lack of oil for the chains include an empty oil reservoir or a blockage due to dirt. The reservoir should be filled with clean oil – not re-used sump oil – and the top of the reservoir should be screwed on securely to exclude dust and dirt.

Chain tensioning is by coil spring, so the spring length should be checked and compared with the instruction book recommendation. Guide blocks are also provided for the chains, and although they have a long working life they should be checked for wear.

Pick-up reel

Pick-up reel problems can include damaged or missing tines, which should be replaced, and the cam follower bearings should be checked. The cams should also be examined for wear, and this applies particularly to machines covering a big acreage each year. The pick-up reel examination should extend to the bearings on the stub augers that draw crop material in from the sides of a wide swath. All round balers have either a rotary feeder or a feeder fork to take crop material from the pick-up. Both types rely on bearings which are subjected to considerable wear, especially in crops grown in abrasive soils. Check the bearings for excess movement indicating wear, and also check that the rotor or fork moves freely.

Some of the pre-season work routine involves access to the rear of the bale chamber, and all round balers have a safety lock to secure the tailgate in the fully open position. Mr Muskett advises engaging the lock and double check that it is secure before attempting to work in the bale chamber. Access to the chamber is essential for checking the combination of belts and rollers in the NH baler. The powered rollers have a gear drive needing a special type of grease, and fresh grease should be added annually on machines exposed to above average use, but in alternate years for those making fewer bales. The rollers should also be checked for rotational wear, and on current NH balers this means releasing the belt tension.

Roller scrapers

Some rollers have scrapers fitted, and these should be adjusted until they almost touch the roller. Accurate adjustment is particularly important for silage, but less so in straw, which is why the job should be included in the pre-season checks. Current NH round balers have endless belts without joints, although a joining kit is a useful accessory for making a temporary repair during the season – in fact the temporary joints sometimes last for years. If one of the outside belts has been joined, it should change places with one of the inner belts where the working tension is less. The belts should be checked for wear, and any loose or damaged edges should be trimmed with a Stanley knife.

Other points to check from inside the chamber include the sensors that measure the bale pressure. Although the sprung plates on each side of the chamber that respond to pressure should be checked for wear or damage, they normally last for 50,000 bales plus, although this is reduced in abrasive conditions. The Cropcutter slicing mechanism on current NH balers is also accessed from the chamber, and the triangular blades can be reversed once when the leading edge becomes blunt or damaged.

Cutting knife

The lock that secures the main net cutting knife is also located in the chamber on current NH balers, and it is painted a conspicuous yellow colour. The lock should be applied and tested before working on the knife, which should be sharp and free from damage. The net-wrap mechanism also includes a rubber pad to tension the net to achieve a more effective cutting action. The rubber pad has a long working life and is reversible, but it should be replaced when damaged or worn. The net feed mechanism should also be checked to ensure the net is running freely.

Current NH balers have a self-contained hydraulic system that rarely needs attention. Ensure it is working correctly by opening the tailgate and checking that a pressure change shows on the gauge on the front of the baler. Checking the action of the tailgate locks is also a useful precaution, and the indicator in the cab will show if one of the spring mechanisms is not working correctly, says Mr Muskett. &#42

Safety equipment is at the top of the winter service priority list. Thoroughly check the drive shaft to make sure the chains are functioning, the cover is undamaged and the yokes in the universal joints are free from excess wear.

The drawbar pin should be the correct size. If the pin is too thin, like the example in the picture, excess movement will damage the ball joint on the end of the drawbar.

Slip clutches on most current round balers are sealed units, but they still need greasing. Being over-generous with the grease can leave an excess which can find its way into the clutch to cause it slip too easily.

Winter service work on the pick-up reel should include checking the cams and cam followers for wear, replacing damaged or missing tines and, in the same area, the bearings in the stub augers should be checked for wear and replaced if necessary.

All-round balers have a safety lock to hold the tailgate in the fully open position. This lock should be engaged and

checked before doing any service work at the rear of a baler that has its tailgate open.

Paul Muskett checks the Cropcutter knives for sharpness and damage. Knives that have already been reversed and are not in good condition should be replaced.

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