Silage Chopper Maintenance

A silage chopper works hard in a short window, so a breakdown costs a lot. Good knife care, regular greasing and a safe lockout habit keep it running through harvest.

Key points

Do a walk-around and grease before each harvest day with the machine off and the key out.
Keep knives sharp and replace them in sets.
Set the shear bar gap using the manual's procedure.
Walk fields for metal and debris.
Lock out the machine and wait for all motion to stop before working on it.

What should you do before every harvest day?

Shut off the engine, remove the key and make sure the cutterhead is at a complete stop before you inspect anything. Check the knives, the shear bar, the feed rolls, the spout, the shields and the driveline. Grease the fittings the manual lists.

Look for loose bolts, cracked welds and worn belts or chains. A short check each morning is cheaper than a stop in the middle of the field.

Keep a small log of knife changes, grease intervals and any odd noises. A short record often shows a trend before a breakdown does. Keep a clean, dry rag and a flashlight in the cab for the morning check. Dark corners hide cracks and loose bolts.

How do you keep chopper knives sharp?

Sharp knives cut cleanly and use less power. Dull knives tear the crop, raise fuel use and wear the machine faster. Many choppers have a built-in sharpener on the machine. Follow the manual for how to use it and how often.

If knives are chipped, cracked or worn thin, replace them. Replace them in sets so the cutterhead stays balanced, and use the knives and bolts the manufacturer specifies. Use the tools and sharpening method the manual describes, and never reach into the cutterhead to sharpen while it is turning.

Sharpen at the interval the manual gives
Replace chipped or cracked knives in sets
Use the specified bolts and torque from the manual
Wear eye protection and gloves

What is the shear bar and why does it matter?

The shear bar sits against the knives and does the cutting as the knives pass it. The gap between the knives and the bar must be set correctly. A gap that is too wide gives a ragged cut, and one that is too tight can cause contact and damage.

Follow the manual's procedure and gauge for setting it. If you are not confident, ask the dealer service department to do it.

A shear bar that has been hit by metal can chip. Check it after any metal strike and replace or repair it as the manual says.

How do you care for feed rolls and the cutterhead?

Check feed rolls for wear, wrapped crop and damage. Remove wrapped material only when everything is shut off and stopped. Check bearings and seals for heat, noise and leakage.

Metal in the crop can wreck a cutterhead. Walk the field for wire, stakes and debris, and use a metal detector if the machine has one and the manual describes it.

Keep your hands out of the spout and the feed roll opening, even if you are sure the machine is off. Use a stick or the tool the manual recommends. If you hear a new knock or rattle, stop and look. A small noise is often the first sign of a bearing or knife problem.

What lubrication and drive checks are needed?

Grease the points shown in the manual, using the grease it specifies. Check gearbox oil at the right level and watch for leaks. Inspect belts, chains and the driveline, including the shield.

Ask the dealer about replacing wear parts in the off season. Order early, because parts for harvesters can take time to arrive.

Keep a list of wear parts and spares near the shop door so harvest does not stall for want of a small item.

How do you work safely around a chopper?

Use a lockout habit. Engine off, key in your pocket, everything stopped, and then work. The cutterhead and rolls can keep turning for a while, so wait. Never rely on a machine appearing to be stopped.

Keep all shields in place. Never bypass interlocks or safety switches. Keep bystanders clear of the discharge spout, since material can be thrown with force. Teach every helper the same lockout routine, and do not skip it on a short stop.

How should you store a silage chopper?

Wash off crop residue, which is acidic and corrodes steel. Check and replace worn parts, grease the machine and store it under cover. Release spring or belt tension if the manual says to.

Take your list of parts to order and your notes about problems to the dealer in the off season. A chopper ready before harvest saves money. Cover the machine or keep it inside, and keep rodents out of the cab and wiring.

When to get help: The dealer service department or a qualified mechanic should handle shear bar setting you are unsure about, gearbox work, hydraulics and drive faults. Follow the manufacturer's manual for lubricants and procedures.

Sources and further reading

Organization homepages are linked so you can search them for current guidance on this topic.

More in Hay, Forage & Livestock Equipment

← Forage Harvester Basics Wagon and Forage Boxes →