21 Aug 2018
Chopper maintenance: Getting the basics right
Before the silage season kicks off, now might be a good time to run through a few final checks of your self-propelled forage harvester.
With expert help, James Rickard runs through a few key areas to check over...
A self propelled forage harvester is a key piece of equipment during silage making and its breakdown, especially in short weather windows, can prove costly, not only in terms of expensive repair bills but also the loss of good quality silage.
An unmaintained forager is also inefficient as tolerances, such as shearbar-to-knife or concave-to-chopping cylinder distances, have grown too large, which leads to increased fuel consumption, as do blunt knives.
To avoid this, Farmers Guardian enlisted the help of Dean Cottey, Claas Jaguar product manager, to compile a checklist of things to look at when getting a forager ready for the season.
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For contractors, many of the tips will come as second nature.
However, if you are a farmer just getting onto the first rung of self-propelled ownership, then these tips should prove useful.
In addition, many of the areas looked at are also worth bearing in mind if you are buying a used forager for the first time.
Representative of a farmer’s machine, our example forager is a type 492, 2004 Claas Jaguar 830.
However, many of our tips also apply to other makes of forager.
PICKUP
The pickup needs to be in good condition for optimum crop flow and to present the crop in a uniform way to the feed rollers.
- Land wheel bearings need checking for wear by giving them a wiggle and their height adjusting depending on conditions. If the pickup is too low it can lead to crop contamination and wearing of parts such as tines and knives.
- Crop press rollers (wind guard rollers) should not have any excessive movement and should roll freely.
- Tine bar cam track thickness and cam track bearings, which are susceptible to seizing up, should be inspected for wear. Excessive wear can be found by rocking the tines back and forth. Sideways movement can also cause the tines to rub on the tine bands, increasing wear rates on both parts.
- Tines need checking for wear and replaced if missing. Missing tines put stress on neighbouring ones, further increasing wear rates.
- Tine bands should be free of cracks and excessive wear. Metal flakes off these can cause unwanted metal detections.
- Intake auger bearings should be free of movement with pickup and auger drive chains kept tight to avoid sprocket wear. If necessary, the auger’s slip clutch will also need adjusting, maintain pickup performance.
- Pickup throat wear takes a hammering and wear plates need to be monitored if holes appear in the feed roller’s cheek plates, and ultimately the feed roller housing, are to be avoided.
FEED ROLLERS
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
ACCELERATOR AND CHUTE
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
CHOPPING UNIT
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
ENGINE AND TRANSMISSION
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
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