Chopper maintenance: Getting the basics right

Feed rollers are the link between the pickup and the chopping cylinder and are under enormous strain to get the crop compressed.

• All feed roller check plates and support bearings need checking for wear. Their supply of grease is essential for trouble free operation. Grease pipes should be free of holes and corrosion
• To prevent feeding issues, feed rollers need to be in good condition and be able to ‘bite’ the crop. Teeth may need changing
• Crop compression comes from four springs which need the correct tension – check manual for settings
• Metal detector clutch needs to be set up properly – see the manual. Its springs, pivots and clutch ramp (ratchet) should all be square to each other for safe operation
• A wear plate which runs across the feed roller housing behind the lower/rear feed roller is also worth a check, as wearing creates a step between it and the shear bar, vastly disrupting crop flow

The accelerator is responsible for blowing the material up the chute and into the trailer.

It rotates at twice the speed of the chopping cylinder (2,400rpm) and therefore is subjected to enormous forces. When this fails, it really fails.

• Check its bearings and grease supply pipes
• Assess the paddle condition, gap size and spout wear plates and compare them with the user manual settings
• Wear plate and chute liner condition should be regularly checked for wear and holes, being replaced if necessary

Between the chopping cylinder and the shear bar is where the battle for chopping efficiency is won or lost. It is not called a precision chop forager for nothing.

• Check shearbar, blade wear and condition. Excessive wear and damaged blades can considerably drive up fuel use as the blades are just bashing the crop, rather than chopping it
• The gap between the shearbar and blades should be as small as possible for efficient chopping. Large gaps can cause inconsistent chop lengths, accelerated wear and, again, increased fuel use
• As blades wear, the shearbar needs adjusting closer to the chopping cylinder, as does the concave. On automatic sharpening foragers, make sure the shearbar adjustment system is not seized. The concave should also be as close as possible to the cylinder without touching to get the most out of the machine
• The sharpening stone needs checking for life and reset for 450 strokes before it bottoms out

With the cost of an engine in the region of £40,000 and a hydrostatic pump and motor costing about £16,000, checking oil levels should be a top priority, says Mr Burnett.

• Depending on workload, engine and hydrostatic transmission oil will need changing annually and levels must be checked daily
• All gearbox levels need checking which includes engine transfer, main range, 4WD transfer, radiator fan, feed rollers, pickup, rear axle and front hubs. For intervals, levels and grade of oil, see the user manual
• Just as important as oil levels, coolant levels need to be checked. Recommended coolant should also be used, as it is also designed to lubricate, rather than a water and antifreeze mix which will corrode liners. Never top coolant levels up by adding water
• Radiators need to be kept clean and require blowing out regularly
• Main belt drive tension needs checking and adjusting if necessary