Why Pre-Season Baler Maintenance Pays for Itself
A hay baler is one of the most mechanically complex implements on the farm — and one of the most expensive to repair when something goes wrong mid-season. Unlike a rake or tedder, a baler failure doesn't just cost you time. It can mean an entire cutting left in the field while you wait on parts, or hay that gets rained on while the machine sits idle.
The good news: the vast majority of in-season baler failures are predictable and preventable. A thorough pre-season inspection and service routine — done before the first cutting — is the single best investment you can make in your haying operation. This checklist covers square balers, small round balers, and large round balers, with notes on where the inspection points differ.
1. Knotter and Twine System (Square Balers)
The knotter is the heart of a square baler and the source of more frustration than any other component. It is also the most maintenance-sensitive system on the machine.
Knotter Inspection Points
- Bill hook: Inspect the bill hook (twine hook) for wear, nicks, and proper spring tension. A worn bill hook is the #1 cause of missed knots. Replace if the tip shows any wear or rounding.
- Twine disc and knife: Check the twine disc for wear on the notch that holds the twine during knot formation. Inspect the twine knife for sharpness — a dull knife leaves long tails or fails to cut entirely. Replace the knife if it won't shave the hair off your arm.
- Stripper finger: Inspect for wear and correct positioning. The stripper finger removes the completed knot from the bill hook — if it's worn or misaligned, knots won't strip cleanly.
- Needle timing: Verify needle timing is within manufacturer spec. Incorrect timing is a common cause of knotter problems that gets misdiagnosed as a knotter defect.
- Twine tension: Check twine tension discs and springs. Incorrect tension causes loose bales or knotter failures.
- Lubrication: The knotter requires precise, consistent lubrication. Clean all knotter components thoroughly, then lubricate every pivot, cam, and bearing surface per the operator's manual. Many knotter problems are simply the result of inadequate lubrication.
Net Wrap and Twine System (Round Balers)
- Inspect net wrap or twine feed rollers for wear and debris buildup.
- Check the net wrap knife for sharpness and correct positioning.
- Inspect the net wrap tension system and verify consistent feed across the full bale width.
- Clean all twine or net wrap guides of crop debris and old twine remnants.
2. Pickup and Feeder System
The pickup is the first point of contact with the crop and takes a constant beating from ground contact, debris, and high-speed operation.
- Pickup tines: Inspect every tine for bends, cracks, or missing pieces. Worn or missing tines leave hay on the ground and create uneven feeding. Replace in sets to maintain balance and consistent pickup.
- Pickup tine holders and cam track: Check tine holders for wear and proper spring tension. Inspect the cam track for wear grooves — a worn cam track causes tines to drag on the ground or fail to retract properly.
- Pickup drive chain or belt: Inspect for wear, stretch, and proper tension. A loose or worn pickup drive causes inconsistent tine speed and poor pickup performance.
- Pickup height and gauge wheels: Set pickup height correctly for your crop conditions. Inspect gauge wheels for wear and verify they roll freely. Seized gauge wheels cause the pickup to dig into the ground.
- Auger or feeder fingers (square balers): Inspect auger flighting and feeder fingers for wear or damage. Check for crop buildup around the auger that could restrict feeding.
- Rotor or stuffer (square balers): Inspect stuffer forks and timing. Verify the stuffer is timed correctly to the plunger — mistiming causes plugging and excessive wear.
3. Plunger and Crank (Square Balers)
The plunger compresses the hay into the bale chamber and is subject to enormous forces with every stroke.
- Plunger knives: Inspect plunger knives for sharpness and correct clearance against the stationary counter-knives. Dull or misadjusted knives cause plugging and poor bale density. Sharpen or replace as needed and set clearance to manufacturer spec (typically 0.010–0.020").
- Plunger head and wear strips: Inspect the plunger head for cracks or damage. Check wear strips or slides for wear — worn slides allow the plunger to rock, causing uneven bale density and accelerated wear on the bale chamber.
- Crank and pitman arm: Inspect the crank arm and pitman (connecting rod) for cracks, especially at weld points and bearing journals. Check the pitman bearing for play or roughness.
- Flywheel and shear bolt: Inspect the flywheel for cracks or damage. Verify the shear bolt is the correct grade and size — never substitute a stronger bolt, as the shear bolt is the only protection for the driveline and gearbox in a plugging event.
4. Bale Chamber and Density System
Square Balers
- Inspect bale chamber sides and top for wear or damage that could cause bales to hang up.
- Check density springs and adjustment mechanism. Verify consistent tension across both sides of the chamber.
- Inspect the bale length metering star wheel and trip mechanism for wear and correct adjustment.
Round Balers
- Belts (variable chamber balers): Inspect all belts for cracking, fraying, delamination, and correct tension. Check belt lacing for wear — a failed lace mid-season means a belt replacement in the field. Replace any belt showing significant cracking or wear at the laces.
- Rollers (fixed chamber balers): Inspect all rollers for wear, flat spots, and bearing condition. Spin each roller by hand and feel for roughness or play. Check roller surface condition — worn or smooth rollers slip on the bale and reduce density.
- Tailgate and latch: Inspect the tailgate hinges, cylinders, and latch mechanism. A tailgate that doesn't seal tightly causes loose, poorly shaped bales. Verify the latch engages and releases reliably.
- Bale density and pressure system: Check hydraulic pressure settings and verify the density control system is functioning correctly. Inspect hydraulic hoses on the tailgate for chafing from repeated opening and closing.
5. Gearbox and Driveline
- Gearbox oil: Check oil level in all gearboxes — main gearbox, pickup gearbox, and any auxiliary gearboxes. Drain and replace oil if it hasn't been changed in the past season. Look for metal particles when draining — a sign of internal wear. Use only the oil type and viscosity specified by the manufacturer.
- Gearbox seals: Inspect all gearbox seals for leaking. A weeping seal caught now is a $20 fix; ignored, it becomes a gearbox replacement.
- PTO driveshaft: Inspect U-joints for wear and play. Grease all U-joint zerks and the telescoping section. Check the slip clutch — exercise it by engaging and disengaging the PTO several times before the first use. Verify the PTO shield is intact and rotates freely.
- Drive chains: Inspect all drive chains for wear, stretch, and proper tension. Measure chain stretch against a new chain — replace any chain that has stretched beyond the manufacturer's wear limit. Lubricate all chains per the operator's manual.
- Drive belts: Inspect all drive belts for cracking, fraying, glazing, and correct tension. Replace any belt showing cracking or significant wear.
6. Lubrication — Full Machine
Lubrication is not a single checklist item — it's the foundation of every other item on this list. Before the first use of the season:
- Grease every zerk fitting on the machine — work through the operator's manual lubrication diagram systematically and don't skip any.
- Pay special attention to the knotter (square balers), pickup cam track, all chain drives, and rotor/roller bearings.
- Use the correct grease type for each application — mixing incompatible greases can cause breakdown.
- After greasing, wipe away excess grease from areas where it could attract crop debris and cause buildup.
7. Hydraulic System
- Check hydraulic fluid level and condition. Fluid that is dark, milky, or has a burnt smell should be replaced.
- Inspect all hydraulic hoses for cracking, chafing, and leaks — pay particular attention to hoses on moving components like the tailgate and pickup lift.
- Check all hydraulic fittings for tightness.
- Verify all hydraulic functions operate smoothly — pickup raise/lower, tailgate open/close, density control.
8. Electrical System
- Inspect all wiring harnesses for chafing, rodent damage, or broken connectors — balers stored over winter are a favorite target for mice.
- Test all monitors, sensors, and warning systems — bale counter, twine/net wrap monitor, moisture sensor if equipped.
- Check and clean all electrical connectors. Apply dielectric grease to prevent corrosion.
- Verify all lights are functional if the baler will be moved on public roads.
9. Structural and Safety Inspection
- Inspect the main frame and tongue for cracks, especially at weld joints and hitch points.
- Check all safety shields and guards — replace any that are missing, cracked, or damaged before operating.
- Verify all transport locks function correctly.
- Check tire condition and inflation pressure on balers with running gear.
- Inspect the hitch pin and clevis for wear — replace if the pin hole is elongated or the pin is loose.
10. Pre-Season Test Run
Before heading to the field, do a controlled test run:
- Engage the PTO at low RPM and listen for any unusual noises — grinding, knocking, or squealing.
- Run the pickup through its full range of motion.
- On square balers, run a small amount of hay through and verify knotter function before committing to a full windrow.
- On round balers, form a test bale and verify net wrap or twine application, tailgate operation, and bale ejection.
- Check for any leaks — hydraulic, gearbox, or grease — after the test run.
Parts to Stock Before the Season
Having the right parts on the shelf before the season starts is as important as the inspection itself. At minimum, stock:
- Pickup tines (full set)
- Knotter bill hooks and twine knives (square balers)
- Shear bolts — correct grade and size for your baler (square balers)
- Belt lacing and repair kit (round balers with belts)
- Drive chain (one full replacement length for your most critical chain)
- Gearbox oil and seal kit
- U-joint crosses for the PTO driveshaft
- Twine or net wrap — verify you have enough for the season before you need it
Downtime during haying season compounds fast. A part that takes 3 days to ship costs you far more than its price tag when hay is ready to bale.
Final Thought
A baler that goes into the season properly serviced will almost always finish the season. A baler that goes in with deferred maintenance will tell you exactly what you skipped — usually at the worst possible moment.
Work through this checklist before your first cutting, keep up with daily lubrication during the season, and address small issues before they become big ones. Your baler — and your hay — will thank you.
Need baler parts before the season? Quality Farm Supply stocks pickup tines, knotter components, belts, chains, bearings, gearbox parts, and driveline components for a wide range of baler makes and models. Contact our team to get the right parts on hand before you need them.
