Buying a used combine means judging a machine by its wear, not its hour meter alone. Check separator hours against engine hours, inspect the rotor and concaves, check the feeder house chain for stretch, worn slats and uneven tension, and look at the header. Then read the service records and run the machine under load. Those checks tell you most of what you need to know before you talk price.
A combine only earns money for a few weeks each fall. During harvest, downtime can disrupt a tight schedule. That is why a careful walkaround beats a quick look at the sticker. If you want to see what is currently available before you start comparing, the Bison Machinery equipment inventory is a practical place to start.
Key Takeaways
Compare separator hours with engine hours instead of reading one number alone.
Inspect the threshing system, feeder house and header as three separate decisions.
Ask for dated service records with hour readings, not a handwritten summary.
Run the machine through a full test sequence before money changes hands.
Confirm dealer or auction terms, fees and pickup details in writing before you commit.
How Many Separator Hours Is Too Many?
There is no single cutoff. Combine separator hours count only the time the threshing system is engaged, so they reflect real crop work. Engine hours include idling, road travel, unloading and waiting on trucks. A machine can show high engine hours and modest separator hours if it spent a lot of time running in the yard.
Compare the two numbers. A wide gap means more engine running time occurred with the separator disengaged. A narrow gap means the separator was engaged for more of the engine's running time. Use that comparison alongside the machine's condition, crop history and maintenance records rather than on its own.
Crop type matters too. Small grains, corn and tough green-stem soybeans wear parts at different rates. Ask what the machine ran, in what conditions, and whether it was used for custom harvesting across long days. Hours tell you how much; the crop history tells you how hard.
What Should You Inspect on a Used Combine?
Work from the front of the machine to the back. A written used combine inspection checklist keeps you honest when a seller is standing next to you and the yard light is fading.
Rotor and Concave Wear
Open the access doors and look at the rasp bars or threshing elements for rounded edges, cracks and missing hardware. Check the concaves for stretched or bent wires, flattened bars and uneven gaps across the width. Worn threshing surfaces can reduce grain quality and capacity, while replacement parts and labor add to the purchase cost. If you need background on the threshing system, this guide on how a Gleaner combine works explains the main components in plain terms.
Feeder House and Drive Components
The feeder house takes abuse from rocks, dirt and crop slugs. Look at the feeder house chain for stretched links, worn slats and uneven tension. Check the floor for thin spots and patch welds. Inspect sprockets for hooked teeth, and look for play in the drive shafts and bearings. Belts and chains elsewhere should match the hours claimed. New belts on a low-hour machine can be routine maintenance or a sign of a recent problem, so ask.
Header Condition
Treat the header as its own buying decision. On a draper, check belt condition, tracking and the cutterbar. On an auger platform, look at the auger flighting, reel teeth and knife sections. On a corn head, check the gathering chains, snapping rolls and stalk rolls. Bent snouts and repaired skid plates suggest hard ground contact.
Grain Handling, Engine and Cab
Check the clean grain and tailings elevators, the unloading auger and the sieves for wear and damage. Look for oil leaks, coolant residue and chafed wiring. Inside the cab, test the monitor, lights, climate control and yield system. Electronics are easy to overlook and expensive to sort out later.
Do Service Records Matter?
Yes. A documented maintenance history is one of the few things that lets you verify a seller's story. Look for oil and filter intervals, gearbox and final drive service, concave or rotor part replacements, and any major repairs with dates and hour readings. Receipts from a shop carry more weight than a handwritten list.
Missing records are not an automatic no. They do mean you should budget for unknowns and inspect harder. Repeated repairs to the same system are worth asking about in detail, including what was replaced and whether the cause was ever found.
How Do You Run a Useful Test Run?
A cold start in a dry lot tells you very little. Plan the test run in order.
Start the engine cold and listen. Watch for smoke, slow cranking and warning lights.
Engage the separator at low speed. Listen for knocking, rubbing or heavy vibration.
Bring it to full speed. Check for belt squeal, shaking and unsteady readings on the monitor.
Raise, lower and tilt the header, and run the reel through its range.
Swing the unloading auger out and in, and run it loaded if any grain is available.
Drive it in both directions, test the brakes and steering, and watch for drift or pulling.
Shut it down and walk around again, looking for fresh leaks and hot bearings.
If you can test the machine in standing crop, do it. Out of season, a thorough yard run plus an inspection by a qualified technician is the next best option.
Should You Buy From a Dealer or at Auction?
Both routes work. The difference is how much you can verify before you commit, so ask the same questions of each seller.
Factor
Ask a dealer
Ask an auction company
Inspection
How much inspection time is available?
When is the preview window, and how long is it?
Test run
Can I arrange a test run?
Is the machine started or run before the sale?
History
What condition and service records are available?
What is disclosed, and what is sold as is?
Cost
What is the complete purchase cost in writing?
What buyer fees or charges apply on top of the bid?
After the sale
What warranty, parts or service support is included?
What are the payment, pickup and transport terms?
Terms vary by dealer and by auction company, so confirm warranty, fees and pickup details in writing before you commit. If you buy at auction, line up parts support in advance. Bison Machinery has parts departments at both North Dakota locations and a dedicated Gleaner combine parts page. Factory-trained technicians handle service work through the Jamestown shop.
FAQs
Frequently Asked Questions
Engine hours count all running time, including idling, road travel and unloading. Separator hours count only the time the threshing system is engaged. Separator hours are the better measure of harvesting work, so always ask for both numbers when comparing machines.
You can handle the visual checks: rotor and concave wear, feeder house chain, header parts, leaks and cab electronics. For drivetrain, hydraulic and engine diagnostics, a qualified technician may help identify issues that are hard to see before a major purchase.
Buying both together simplifies fit and hookup, but only if the header suits your crops and acres. Inspect it separately for cutterbar, belt, auger and reel wear. A worn header can affect cutting and crop flow even behind a sound combine.
Shopping after harvest or over winter gives you time for inspection, repairs and parts ordering before the next season. Shopping earlier also gives you more room to order parts and finish any needed repairs before harvest starts.
Plan for wear parts, fluids and filters, transport, and any repairs found during inspection. Costs depend on the machine's condition and your crop mix, so get a written repair estimate before closing rather than guessing at a number.
Making the Call on Buying a Used Combine
Before buying a used combine, compare the hour readings, inspect the threshing system and header closely, read the records, and run the machine before money changes hands. Then decide whether a dealer purchase or an auction fits your risk tolerance and your timeline into next fall. If you need service support for a Gleaner machine, contact Bison Machinery's service department to discuss service needs.
Bison Machinery has been a family-owned North Dakota equipment dealer since 1974, with locations in Jamestown and Casselton, factory-trained technicians and a stocked parts department. Call the branch nearest you or browse current machines at Bison Machinery.
