Corn harvest is the worst time of the year for a breakdown in the field. Taking time to thoroughly inspect your combine before you even turn a wheel can go a long way towards preventing maintenance issues that can rob you of valuable time and money when it’s time to get your corn crop in the bin.

Here are a few tips and ideas as you start your preharvest combine inspection.

Before you start harvesting, give your combine a check-up

DO IT NOW: Before you start harvest, give your combine a thorough inspection, inside and out. Look for worn parts, check all fluids, replace if necessary. Electronics and sensor technology should be inspected and tested by the dealer.

Today’s combines are well-built, but the process of harvesting corn, by its very nature, requires a lot of wear and tear. Determining just how much wear and tear your machine has taken – and more importantly how much it can take moving forward – is a critical task well before a single kernel is harvested.

According to Dennis Bollig, Dragotec USA president and Fenton, Iowa, farmer, the average farmer runs a lot more acres through a combine now than 20 years ago. “Inspecting a combine often requires taking a guess on whether specific components are going to make it through the season or not,” Bollig says. “Is it 25% or 50% worn out? What are the chances of having to replace that part? Answer these questions through a thorough inspection. Run the machine and have somebody sit in the cab from a safety standpoint. Somebody’s got to do a walk around with that machine running who can help you see, hear or smell if you have potential maintenance issues.”

Preharvest inspection needs to be thorough and complete

Bollig encourages farmers to ask whether their last harvest was a wet, drawn-out affair or quick and dry? “It’s important to look back on the conditions you faced the last time your combine was in the field, since that perspective can help you start your preharvest inspection off on the right foot.”

“With a wet harvest, you’re more likely to pick up more dirt moving between wet fields. Mud can build up in the bottom of an elevator, create more wear on the paddles and stick to certain parts of the combine. It can fill up the rasp or concave bars in the initial separation and create some grain loss,” Bollig says. “With drier conditions, you have a lot more dirt and dust to clog air filters and you have to watch for the buildup of debris from a fire hazard standpoint. From a temperature standpoint, you’re running in higher ambient temperatures, and you’ve got to make sure you pay close attention to any gearboxes and components that in a cool, wet fall, might be less apt to cause issues.”

Electronics and sensor technology are best tested by dealer

Even if you can inspect and repair your machine’s mechanical components, the latest electronics and sensor technology often require a trained eye when inspecting your combine before harvest begins.

“With so much technology in the combines, we typically have a yearly inspection done by the dealer. That doesn’t mean he has to do all the work, but you want to get a professional eye to look at it. The same goes for diagnostics,” Bollig says. “It starts with taking it to an expert to hook it up to a computer to test those sensors and diagnostic electronics.”

However, not every tech component requires an expert’s eye

A common issue with any machinery stored for long periods of time can be especially damaging to electronic components, wiring and sensors, says Iowa State University Extension (www.extension.iastate.edu) ag engineer Mark Hanna. “If you have rodents, connectors can be damaged. You may have mice chewing the wiring,” he says. “It’s probably been 10 or 11 months since you’ve run that machine, so it’s important to watch for rodent damage.”

Fluids need particular attention, and not just in the engine

When checking the engine compartment and other areas of the combine, pay close attention to fluids. Any fuel may need to be drained and replaced if it’s been in the combine for an extended time, according to Hanna. It’s also important to check coolant to make sure it’s got enough working life left to keep engine temperatures in the optimal range, especially if the machine is going to cover a lot of acres this fall.

“Any liquid is important to check and replace if necessary. It’s important the coolant and radiator are cleaned up. If you’re going to get the best heat rejection out of that radiator system, you need to make sure it’s in good shape,” Hanna says. “It’s also especially important to make sure whatever fuel is in the engine is okay, particularly biodiesel.”

All gearboxes and bearings should be filled with oil or grease

Checking fluids shouldn’t be limited to the engine; Bollig says some slight leakage or vapor loss may be unavoidable, but all gearboxes and bearings should be at their oil or grease capacity.

“Running these modern synthetic oils, you can have some slight leakage around stalk roller seals. It’s not uncommon, but most gearboxes are typically sealed up fairly well,” he says. Synthetic oil — like that in the Dragotec (Dragotec.com) USA GT corn head’s gearboxes — doesn’t vaporize like conventional oil or grease. “It’s important to check the oil on those gearboxes themselves.”

Chains and friction points need to be inspected for wear

Anywhere there’s repeated friction, like the roller chains on a corn head, there’s the potential for wear and premature part failure. With any chain that has noticeably loosened, stretched or become “sloppy,” the likelihood that part will last through harvest’s end falls. And, the failure of a chain-driven component can have big impacts elsewhere on the combine, making it an important area of focus during a preharvest combine inspection.

“When a chain continues to run past its prime, it’s stretching quicker, and if somebody’s not maintaining the proper tension, chains are known to start to jump the teeth on the gear driving them,” Bollig says. “That effect sends a shudder through the whole machine, and you can see it affecting bearings and anything in the vicinity gets the impact of that shudder.”

Also be sure to check gears and pins that drive the chains

When inspecting chains, Bollig also suggests making sure you check the gears and pins driving them. In gauging whether those components will last through this fall’s harvest, consider the conditions in which you harvested corn in previous seasons. “If you have a fall during which you have a lot of tough, wet conditions and stalks are tough, you could have some potential plugging issues that put extra strain on those rollers,” he says.

The corn head drive system is another area to inspect carefully, both its chains and the sprockets and gears driving them, Bollig adds. Though premature failure is a concern with the drive system, so too is lost efficiency as the components age.

“You’ve got to inspect it for wear and be sure you can make an educated guess whether it’s got enough life left in it to run all season. You know your acres and can base it off of that. The more it wears, the less efficient it is over time,” he says. “You’re checking sprockets, too. You can put a new chain on but maybe the sprocket has a lot of wear on the teeth.”

Threshing and auger components affect harvest efficiency

Even the smallest amount of damage in a concave section or rasp bar can have a considerable influence on your harvest efficiency and potential yield loss.

“Down in the threshing and separation area, people will take a close look at their rotor and concave. You’re looking for damage that may be relatively minor. Maybe you have a small rock or something go through, so you need to replace a concave section,” says Hanna. “Down in the cleaning shoe area, check condition of the sieve. If something’s gotten dinged or banged up, it needs attention. You’re looking for general wear.”

Finally, check the flighting on all augers. Though damage is less likely in this part of the combine, wear can sometimes leave sharp edges on the flighting, leading to grain damage. “It’s probably in good shape, but it does wear over time. It is something that may need to be looked at,” Hanna says. “If you have some really sharp edges, you can cut some of the grain. If that’s the case, you’re going to degrade your corn quality.”

Not just yield loss, grain quality consequences also important

The right attention to threshing components has considerable implications when it comes to overall yield, but not just in terms of yield loss during harvest. Wear on threshing components can cause grain quality issues, making it important to ensure augers, concaves, sieves and tailing systems are in good shape before entering the field in the fall.

“It’s not just losses, but it’s also the quality of the corn that ends up in the grain tank. A lot of folks are storing their grain themselves, on the farm. They want to make sure that seed coat surface is intact,” Hanna says. “Grain tends to go out of condition faster if you’re not careful on your settings on your combine and how you’ve harvested.”

If you’re looking to start your combine preharvest inspection, contact your local service technician or dealership. For more information on Dragotec USA corn heads, go online to http://www.dragotec.com.