How To Prepare Your Combine For Peak Performance: A Field-tested Maintenance Guide

Did you know that effective combine maintenance can help you avoid costly breakdowns during peak harvest times?

Regular inspections and timely repairs aren't just good practice—they're essential for maximizing your harvest efficiency. A thorough harvester maintenance routine extends the life of your equipment while ensuring it delivers the performance your crops deserve. Before the combines roll, we recommend creating a detailed combine harvester maintenance checklist that covers everything from technology systems to fluid levels.

In fact, a well-maintained combine gives you the best chance at producing the harvesting results you want. Replacing worn components like rasp bars at the right time is one of the most effective ways to prevent grain damage, while inspecting machine concaves can safeguard against poor threshing.

In this guide, we'll walk through the essential steps to prepare your combine for peak performance this harvest season—from cleaning and safety checks to component inspections and final pre-field preparations.

Start with a Clean and Safe Machine

A thorough cleaning routine sets the foundation for efficient combine maintenance. Initially, removing all debris prevents mechanical issues and eliminates hiding places for pests that could damage your machine during storage.

Clean filters, grain tank, and threshing system

Begin your combine harvester maintenance by thoroughly vacuuming the grain tank from top to bottom. Pay special attention to ledges, steps, lights, sensors, and wiring around the cab window. Clean around and inside the bubble-up intake auger, lowering it to different positions to access material underneath. Next, vacuum biomaterial from the cross augers' floor and use a smaller flexible hose to clean the grain tank sump.

For the threshing system:

• Open the rock trap door to loosen and dislodge plant material
• Remove access panels and concaves to clean the rotor/cylinder area
• Use compressed air first, followed by vacuuming to remove stubborn debris
• Clean the chopper by removing plant material from both ends of the rotor/cylinder

Open the sieves to their maximum width and force compressed air through them. Additionally, clean the elevators by opening the lower doors and shaking the conveyor chains to dislodge material.

Inspect for rodent damage and debris

Rodents pose a significant threat to inactive machinery, particularly combines that harbor food sources and provide shelter. With new combines easily worth a quarter of a million pounds, the fire risk from rodents gnawing electrical wiring must not be underestimated. Wiring, hydraulic hoses, drive belts, and electrical components are especially vulnerable, making thorough inspection crucial.

Check for any damaged wiring, chewed hoses, or signs of nesting. Remove all grain and chaff inside and out—eliminating food sources and nesting materials dramatically reduces rodent problems. Furthermore, examine the engine compartment carefully, as rodent damage to electronic components, wiring, and sensors is common in machines stored for extended periods.

Check fire extinguishers and safety decals

Keep two fully charged fire extinguishers on your combine—a 10-pound unit in the cab and a 20-pound unit mounted at ground level. ABC fire extinguishers are recommended for farm machinery as they're effective against fires in their initial phases.

Moreover, inspect all safety decals for visibility and legibility. These color-coded markings play a critical role in operator safety. Clean decals with mild soap and water, avoiding solvent-based cleaners that can cause damage. Replace any damaged or illegible decals immediately—if you're wondering whether it's time to replace a decal, the answer is probably yes.

Inspect Key Components for Wear

Examining critical wear points regularly saves you from costly field breakdowns when you least need them. Systematic inspection of key components ensures your harvester delivers optimal performance throughout the busy season.

Feeder house and chains

The feeder house initiates the harvesting process, making its condition paramount to overall performance. Check the feeder chain for proper tension – chains measuring 3% longer than their original length should be replaced immediately. Inspect slats for cracks or breaks and examine front feeder drum bearings on both sides. Subsequently, check that your feeder chain distance remains even across both sides to prevent chain jumping, which causes downtime. Additionally, look for wear on the sheets at the bottom of the feeder house and make sure the anti-swivel bolts remain in place.

Belts, chains, and sprockets

Worn drive components significantly impact your combine's reliability. Examine chains for proper tension and replace sprockets showing excessive tooth wear or cupping. For belts, look for cracks that run across all three ribs in the same location – a clear sign replacement is needed. Check all variable speed drives, sheaves, and bearings for smooth operation. Consequently, replace any chain exceeding the 3% elongation threshold, and remember to always replace chains and sprockets as matched sets for best performance.

Concaves, rasp bars, and knives

Threshing component wear directly affects grain quality and separation efficiency. Inspect rasp bars for three specific wear patterns: center portion wear, leading edge deterioration, and serration height reduction. Replace rasp bars when serrations measure less than 1/4-inch at their deepest point. For concaves, check for rounded or bent bars, missing wires, and residue buildup. Remember that even minor damage to these components can dramatically affect harvest efficiency and yield loss.

Augers, elevators, and sieves

These components move your harvested crop through the combine. Check the clean grain and tailings augers for sharp edges or bowing, which diminishes grain-moving capacity. Inspect elevator chains by removing drive belts and manually rotating the assembly to find worn paddles or sagging chains. For sieves, pull them out and examine for bent or missing fingers, which prevent proper closing and opening. Furthermore, inspect the frames for cracks, especially at corners, ensuring solid frames that won't operate loosely.

Test and Calibrate Technology Systems

Modern combines rely on sophisticated technology systems that require regular updates and calibrations to ensure peak harvest performance. Proper maintenance of these systems directly impacts your yield data accuracy and overall machine efficiency.

Update software and firmware

Keeping your combine's digital systems current is as vital as mechanical maintenance. Software updates often include bug fixes and functionality enhancements that improve performance. For John Deere equipment, check for updates like the May 2025 Software Update 25.2 (version 10.31.3676-103) for G5/G5Plus displays and Generation 4 displays. Similarly, StarFire™ receivers require periodic updates to maintain positioning accuracy.

To update effectively:

1. Back up your existing data before installing any updates
2. Verify compatibility with your specific equipment model
3. Download the latest software from the manufacturer's support website
4. Follow installation instructions carefully to avoid interruptions

Calibrate yield monitor and moisture sensors

Accurate yield data requires proper sensor calibration. First, perform temperature calibration when the combine is cool—ideally at the start of the day before the machine generates heat. The sensor reading should match the surrounding air temperature. Next, calibrate the moisture sensor for each crop type you harvest, treating wet corn (>20% moisture) and dry corn (<20%) as separate crops.

For yield calibration, complete calibration loads near the same time once per season per crop. Aim for uniform crop conditions and collect loads between 3,000 to 6,000 pounds. Afterward, select calibration loads with percentages between -3.0 and 3.0 for best results.

Check electrical wiring and sensors

Electrical issues can cause mysterious performance problems. Therefore, inspect all cables and connections for rodent damage, wear, or poor connections. Look specifically for:

• Severed cables or loose connections
• Dust and debris blocking sensor contacts
• Corroded battery terminals
• Damaged proximity sensors

Clean sensor contacts using compressed air and isopropyl alcohol if dirty. When testing electrical components, always use proper testing equipment like voltage testers rather than screwdrivers that make you part of the circuit.

Final Checks Before Field Entry

Prior to getting your combine into the field, these final checks are vital for both performance and safety. These last-minute inspections often prevent costly breakdowns and ensure your harvester performs at its peak when you need it most.

Check tire pressure and track tension

The condition of your combine's ground contact components directly impacts both soil health and machine performance. For optimal efficiency, inflate tractor tires to the lowest recommended pressure for your specific fieldwork. Radial tires on tractors typically have different inflation ranges for fieldwork versus road travel. Under-inflation can cause dangerous sidewall buckling, while over-inflation creates excessive bounce and increases soil compaction.

To properly check tire pressure:

• Use digital, pencil, or dial gages with increments of at least 1 psi
• Measure when tires are cold (readings can be 1-3 psi higher when warm)
• Position valve stems consistently for all tires (bottom readings can be 1.5 psi higher)

For tracked combines, inspect track tension and condition thoroughly, removing any lodged debris that could cause operational issues.

Inspect hydraulic lines and fluid levels

Hydraulic system failures rank among the most common harvest-halting problems. Examine all hoses for bulges, delamination, pinhole leaks, and connection point issues. Any hydraulic component failure can cause significant damage to pumps, motors, and cylinders if left unchecked.

Alongside hydraulic lines, check all fluid levels including brake fluid, engine coolant, and steering fluid. These systems rely on proper fluid levels to function optimally. Low fluid levels in any of these systems can lead to dangerous situations such as brake failure or engine overheating.

Verify lighting, SMV emblems, and road readiness

Your combine's visibility on public roads is a legal requirement and safety necessity. Test all exterior lights including headlights, taillights, turn signals, and brake lights. The slow-moving vehicle (SMV) emblem must be:

• Visible from 500 feet to the rear
• Mounted with the triangle point facing upward
• Positioned 10 degrees from vertical
• Placed 2-10 feet above ground
• Centered or as near left-center as possible
• Securely attached

Replace any faded SMV emblems, as they lose effectiveness over time. Keep in mind that SMV emblems are only for vehicles traveling under 25 mph – they should be removed or covered when being transported at higher speeds.

Conclusion

Preparing your combine for peak performance requires dedication and attention to detail. Most importantly, a systematic approach to maintenance dramatically reduces the risk of costly breakdowns during critical harvest periods. After all, each hour of downtime during harvest can significantly impact your bottom line.

Throughout this guide, we've covered essential maintenance procedures that work together to ensure your combine operates at its best. Cleaning thoroughly removes debris that could cause mechanical failures or fires. Subsequently, inspecting key components like feeder houses, belts, chains, and threshing elements prevents wear-related issues. Additionally, modern combines demand regular technology updates and calibrations for accurate yield data and optimal performance.

Final pre-field checks serve as your last defense against unexpected problems. Therefore, verifying tire pressure, hydraulic systems, and safety equipment should become second nature before heading to the fields.

Remember, preventative maintenance isn't just about avoiding breakdowns—it's about protecting your investment and maximizing harvest efficiency. Your combine represents a significant financial commitment, thus deserving proper care through every season. Accordingly, the time spent on maintenance now will pay dividends when your machine performs flawlessly during the demanding harvest season.

We recommend developing a maintenance schedule and keeping detailed records of all work performed. This approach helps track component lifespans and identifies recurring issues before they become major problems. Certainly, a well-maintained combine harvests more efficiently, preserves grain quality, and lasts significantly longer.

Your harvest success begins with your maintenance practices. Take these recommendations seriously, implement them thoroughly, and your combine will reward you with reliable performance when you need it most.