Maintaining a John Deere Baler Wrapper

Although this guide looks in detail at servicing the John Deere 678 Wrapping Baler, the same principles apply to not only the firm’s popular 575 baler, but other makes as well, says Roy McIntyre, a technician with Robert Cole Agricultural Engineers at Holsworthy, Devon.

The first job is to check the pto shaft guards for damage and replace if necessary. Then remove the shaft and check the universal joints (UJ) for wear, paying particular attention to the wide angle joint.

Next stop on the driveline is the pto cam clutch, which is splined on to the gearbox and secured by a bolt. Inside are two plungers, which lock into the sides of the housing and are held in place by two strong springs.

“Check the roll pins which fix the springs to the caps are not bent or worn.” advises Roy.

“Inspect the cam lobes and inner ring for excessive wear. Then check the spring length, which should be 127mm to provide the correct torque setting.

“Adjustment requires removing the roll pins and adjusting the position of the caps to set the correct length.

“This is probably best left to a trained dealer because over-tightening the clutch will permit excess torque to be transmitted, which can overload the whole drive train.”

Next in line is the gearbox. It holds exactly 2 litres of Extreme-Gard LS90 gear oil. But you need to remove the level plug to fill the oil, which means it is easier to drain all the oil and refill. “This way the oil is changed and filled with the correct amount every season,” explains Roy.

Drive from the gearbox is transferred to both sides of the machine via shafts. Check and grease their UJs. On the left (nearside) is a large chain which drives the rotor. Check the tension on this and adjust the idler.

“Also check the rollers have not opened on the joiners inside the chain,” he advises. “This applies to all the chains”.

Sprockets transmit drive to a smaller chain which powers the pick-up. It is important to remove the guard because debris can collect behind here and negate the work of its oiler.

“The chain costs about £25, so we feel it’s always best to replace this every season, and considering the work it does, that is cheap insurance against a costly breakdown in the height of the season,” says Roy.

Moving down to the pick-up, check the tines are not worn or bent - the outer ‘offset’ tines are thicker than the others. Remove and inspect the cam track, which can wear. Then check the condition of the small bearings which sit on the ends of the tine arms and run in the track, as well as their small shafts.

On the right (offside) is the main drive chain which powers two sets of chains - one to the rollers on the door and the other to the rollers at the front of the chamber. Check and set the spring tension by adjusting the idlers’ nuts so the spring lines up with the end of the plate.

Check the rollers’ bearings, paying particular attention to the starter roller in the base and the one behind - these do the most work. Use a long bar to lever them up looking for any movement.

Replacing these bearings is best left to a dealer – the nut on the tapered shaft on the starter roller needs a torque setting of 860Nm - very, very tight! Check all the grease tubes are still going to the bearings.

Ensure the rotor knives are sharp - they need replacing if the scalloped edge is worn away. Dealers will sharpen these - a process which will help cut fuel consumption by 10 per cent.

Moving up to the net wrap system, the rollers need to completely clean and free from nicks or cuts. “You can shine off any marks on the stainless roller with emery, but not too much because this can cause it to rust. When really clean, apply a light coat of silicon spray - we use cockpit shine,” advises Roy.

“Also check the lid closes properly because this is an integral part of the system. Use WD40 on the linkages.”

Check the net roller drive belt and brake pad for wear. Also, wearing thick welding gloves, remove the knife and sharpen with a flat sander or fine file. “Also clear any debris from behind the little net wrap trigger switch,” adds Roy.

When it comes the wrapper, Roy says these are usually very reliable and all run by an electronic sequence.

“The most important point is to ensure the roll dispensers spin freely and the stretch rollers are spotless,” says Roy.

“The film’s adhesive sticks to the rollers and collects dust – it is crucial this is cleaned off. It is also a good idea to periodically change the film knives.”

Lastly, check all the switches and wiring, but there is little there to go wrong mechanically. The table belts should not have cuts, but these also do last well.

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