It starts with an odd noise, a warning light, a bad digital readout, or worse — complete shutdown.

From the minute you pop the cab door open, profit and efficiency quickly head south. For a custom harvester this can mean $1,000/hour lost. Could you have avoided this all-too-familiar scenario? Probably.

Today's well-engineered self-propelled forage harvesters are built to turn high-tonnage forage into high-quality feed at a rapid pace. But that proclamation starts to wane with every pass across a green field as fast-moving parts on greased bearings cut through dust, debris and dirt-laden stalks and stems.

Sharp and clean is a motto most manufacturers tout when asked how operators can keep from popping that cab door too often.

“General maintenance on a daily basis — such as greasing, sharpening knives and setting shear bars — is one of the most overlooked aspects of harvest,” says Tim Meister, John Deere's hay and forage marketing manager.

Regular knife sharpening and shear bar adjustment are critical so increased gap in this area won't accelerate wear.

“Pay attention to crop type and conditions. These two parts usually wear faster in alfalfa than in corn because you're picking up more dirt and sand,” Meister adds. “And don't just think knife sharpening is the key, because actually you should be adjusting your shear bar twice as often as you sharpen knives.”

Phil Wright, New Holland's hay and forage product specialist, adds knife bolts to the list of components that need regular attention.

“Operators need to take a few critical minutes to make sure bolts are torqued properly, especially when you consider the shear force placed on this component by a 600-hp engine,” he says.

Regular cleaning of the machine must go beyond the cosmetic and the visible, says Jon Pinner, regional service manager for Claas of America.

“We've seen lots of customers who just clean the outside of the machine and the cab, and miss the critical cutting areas,” says Pinner. Operators need to remove material buildup in and around all moving parts, behind shields, in the corn cracking area and beyond.

“Improper cleaning can quickly and easily lead to maintenance and functional problems,” he adds.

Scheduled preventive maintenance is a must, especially in the West, where machines can run up to 2,000 hours a year. Contract harvesters in that region typically run several choppers, and often rotate two or three of them into the shop every night during the busy season.

“This helps them monitor and replace parts before downtime happens,” says Bob Armstrong, Claas sales manager.

All new New Holland self-propelled harvesters come with a two-year “Triple Check” maintenance program.

“At the end of the season, or between seasons in busy Western markets, our dealers use a lengthy preventive maintenance checklist to prepare machines for the following season, at our cost,” says Wright.

Common wear items include shear bars, main wear plates behind the accelerator, corn cracker rollers, blower bands, blower panels, cutter head bands, spout liners, knives, knife bolts, corn head cutting blades and more.

Deere's Meister agrees that a little preventive maintenance shop time exploring known wear items is a sound investment. For example, he suggests taking a few minutes to apply the “take a nickel and leave a dime” theory. That is, the paddle blades should pass over top a 1 mm-thick dime, but must be adjusted if they pass over a thicker nickel.

“These few minutes can save you at least a half-hour change job in the middle of a field with seven trucks lined up waiting,” says Meister.

“Operators sometimes just replace the worn liners and overlook the critical adjustment needed to keep this component from robbing too much horsepower,” Wright adds.

Judging wear on other parts, such as a crop processor (corn cracker), can baffle even astute operators.

“Since it's harder to judge 1 or 2 mm of wear on a part with many teeth, we find it more accurate to measure the circumference of the processor,” says Meister. “In fact, we just produced a Deere measurement gauge this year to ease this process.”

Tough crops can play a huge role in the amount of maintenance and parts replacement needed.

Pinner points out that California's winter small-grain forage harvest is the toughest test on a chopper. That's because the flow is uneven, the crop can yield 20 tons/acre, and it contains a lot of residue and dirt.

“Conditions like this can lead to wear plates being replaced four or five times a year in the West, where 1,500-2,000 hours a year per machine take a toll,” says Pinner. “But in the East and Midwest, wear plates can last two or three seasons because harvesters may run only 500 hours per year.”

For these tougher crops and conditions, Claas and John Deere offer a line of heavy-duty parts to reduce the need for multiple replacements of wear parts.

“But if a customer can run a full season on standard parts, he doesn't need heavy-duty parts,” says Pinner.

Not to be forgotten, all sources note the importance of regular lubrication. Auto lube systems are standard on larger Claas and Deere machines, and New Holland automatically adds them to machines sold in the West.

“This is a key feature desired by our large Western customers, but it's not as heavily demanded in the Midwest and East,” Wright says.

“Our auto lube system is standard and is a major contributor to reduced downtime,” Armstrong says. “By getting a predetermined amount of grease to 28 points on the machine every 15 minutes, you never run the risk of damage from under- or over-lubricating. It also provides tremendous resale value.”