Used Grain Cart Inspection Checklist: What to Check Before You Buy

Buying used · 8 min read

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A used grain cart is one of the simplest machines you can buy secondhand — a tub on wheels with an auger in the bottom. But simple doesn't mean trouble-free. Cart augers and gearboxes take enormous loads every harvest, grain eats steel slowly, and a cart that looks straight from the road can hide worn flighting, a tired gearbox, or scales that lie. Here's what to check before you buy.

The tub: dents, rust, and grain leaks

Start by walking the whole tub, inside and out. Dents in the sidewalls are cosmetic unless they're deep enough to kink the steel. What you're really looking for is rust — grain carts hold moisture against steel, especially where dust packs into corners and around the auger troughs. Look for rust at the welds, along the bottom seam where the tub meets the undercarriage, and around every bolt hole and bracket. Tap soft-looking spots with a screwdriver handle; solid steel rings, rotten steel thuds.

Then look for leaks. A cart that dribbles grain everywhere costs you in dockage and cleanup. Check the gate at the bottom of the tub — it should close fully and seal. Look at the joints between tub panels and around any auger covers. Ask to park it on clean concrete and load it, or at least run grain through it; leaks that are invisible on an empty cart show up immediately under load.

Check the inside walls for caking. Heavy caked-on grain residue, especially from a cart that's been parked full or put away dirty, holds moisture and accelerates corrosion from the inside. A quick scrape is normal; inches of hard pack in the corners is a maintenance story, not a fluke.

The auger: flighting, trough, and bearings

The auger is the working heart of the cart, and it's the first place money goes on a worn machine. Grain is abrasive — it wears flighting thinner and shorter over time. Sight down the length of the horizontal auger and look at the flighting. Worn flighting loses height first, then develops knife-edge thin spots. On the vertical unloading auger, the wear concentrates where grain changes direction — at the base elbow and at the discharge. If flighting looks polished and thin at the bends, it has lived a hard life.

Check the trough or tube the auger runs in. Excessive clearance between the flighting and the trough wall means grain is slipping back instead of moving forward — you feel it as slow unload rates and hear it as extra grinding. Rotate the auger by hand (power off, PTO disconnected) and feel for grinding or catching. Any bearing you can turn by hand should turn smooth, not lumpy.

Work every auger cover and access panel. Panels that are rusted shut or missing mean the bearings and driveline inside haven't been greased or inspected in a long time — and the seller doesn't want you looking in there. Pull a grease zerk cover and check that the bearings take grease rather than spitting it out of a blown seal.

Gearbox, PTO, and driveline

The gearbox drives the auger under full load, and it's not a component you want to rebuild in the middle of harvest. Check the gearbox oil level and condition — pull the plug or sight glass. Oil that's milky (water) or full of metal flakes is a red flag. Sniff it; burnt-smelling oil means it has been run hot, which usually means overloaded or low on oil.

With the PTO disconnected, rock the gearbox input shaft and the output shafts and check for play in the bearings. Then look at the whole driveline: the PTO shaft should have a solid, intact guard — torn or missing guards are a safety deal-breaker, full stop. Check the U-joints for play and make sure the shaft telescopes freely without binding. A shaft that binds under load puts shock into the gearbox every time it flexes.

If the cart has a hydraulic drive or electric-over-hydraulic controls, cycle every function — auger engage, gate, fold, spout position — and watch for smooth operation with no jerking or hesitation.

The unload rate tells the truth

A cart that unloads slowly is a cart with worn flighting, a tired gearbox, or a clearance problem — or all three. If you can, time a full unload with actual grain. Compare against what the seller claims and against your combine's output: the cart should keep pace comfortably, because any time the combine waits on the cart, harvest stands still.

Watch the discharge during the run. Grain should flow smoothly and evenly with no surging. Surging usually means the auger is slipping grain back through worn clearance, and it'll get worse, not better. Listen to the gearbox and auger under full load — bearing noise and grinding that you couldn't hear on an empty run will show up under load.

Running gear: axles, tires, and brakes

Grain carts are heavy when full, and the running gear takes the punishment. Check both axle stubs and the main frame for cracks, especially at the welds where the axle meets the frame. Look for signs the machine has been overloaded: bent rims, cracked hubs, or tires wearing unevenly because something is bent.

Tires on a cart often rot before they wear out, since the machine sits most of the year. Check the sidewalls for dry rot cracking and look at the date codes — tires past eight years old are living on borrowed time regardless of tread. A blown tire on a loaded cart is not a roadside inconvenience; it's a harvest stoppage.

If the cart has brakes, test them loaded. A machine that weighs many tons full needs working brakes, no exceptions. Check the parking brake holds on a slope.

Scales: the number you're buying by

More and more carts have weigh systems, and buyers trust them without checking. Don't. A scale that reads wrong has been telling the operator wrong numbers all season — which means the records of what this cart carried are fiction.

Test it. Put a known weight in the cart and compare. A full 55-gallon barrel of water is about 460 pounds; three of them give you a rough check at 1,380. If the display reads meaningfully off, the load cells, the display, or the calibration are suspect. Run the auger while watching the display — on a good scale the weight drops smoothly; a scale that jumps, freezes, or resets has an electrical or load-cell problem.

Check the wiring to the load cells and the display for chafing and green corrosion, and make sure the cart's tongue or suspension points that the load cells mount on are intact — bent mounting hardware flexes and reads wrong.

Hitch, frame, and safety equipment

Check the hitch and tongue for cracks, wear in the hitch hole, and a solid jack stand. Look at every safety chain and the hydraulic breakaway connection — if the cart has hydraulic brakes, the breakaway system should be complete and functional. Slow-moving-vehicle signs and lights should be present and working; this machine runs on public roads every fall.

Records to ask for

Ask for maintenance records: auger and flighting replacements, bearing and gearbox work, tire replacements, and any scale calibration or repairs. Ask what crops it ran (corn and wheat wear differently than soybeans), how it was stored (inside and washed beats outside and dirty), and whether it ever sat loaded between harvests. A cart that lived a clean, inside life shows it. A cart that was parked full in the yard every October tells you that, too — in the bearings, the tub, and the gearbox.