Square Hay Baler Maintenance Schedule: 50-Hour & 200-Hour Guide

Grease all fittings

Work through the full lubrication chart — all U-joints, pickup reel bearings, plunger rails, knotter cam followers, and any other grease point specified in your model’s manual. Do not skip fittings that “look greased” — old grease carbonises and needs fresh grease behind it.

Check chain tension on all drives

Press each chain at mid-span — maximum 15–20 mm deflection. Chains stretch under initial load during the first hours of operation each season. Tension check at 50 hours catches this early elongation before it causes sprocket wear.

Inspect pickup tines

Walk the full pickup width. Replace any bent tine that deviates more than 15° from correct position and any broken or missing tine. Check tine mounting bolt torque.

Check knotter system

Cycle the knotter manually and inspect: needle tip condition, bill hook opening and closing, knife edge condition. Clean chaff and twine fragments from the knotter box — debris accumulation in the knotter box is a leading cause of mid-season mis-ties.

Inspect PTO driveshaft

Check U-joint play — any roughness or binding in the U-joint rotation indicates worn bearing cups that need replacement. Confirm the guard spins freely and is not cracked or damaged. A damaged guard allows twine to wind into the driveline.

Check fasteners on wear areas

Vibration loosens fasteners in high-stress areas — particularly knotter mounting bolts, pickup tine hardware, and bale chamber guide rail bolts. Tighten any that have worked loose.

Chain wear measurement

Use a chain wear indicator or measure 12 links and compare to new-chain specification. A chain that has elongated more than 1.5% of its original pitch length should be replaced — worn chains rapidly destroy sprocket teeth.

Sprocket tooth profile inspection

Worn sprocket teeth develop a hooked profile — the leading face undercuts and the tooth becomes asymmetrical. A hooked sprocket will eject a correctly tensioned chain under load and must be replaced together with the chain.

Needle bushing play check

Grip the needle arm and measure side-to-side play. More than 4 mm of play at the needle tip indicates bushing wear that will progressively worsen knot quality. Replace bushings before the next season’s first cutting.

Plunger slide rail condition

Inspect the plunger guide rails for grooves, scoring, or deformation. The plunger must slide smoothly through its full stroke — any resistance or binding under a 200-hour inspection indicates accelerating wear that should be addressed before another full season.

Pickup reel bearing inspection

Spin the pickup reel and listen for bearing roughness or grinding. Any roughness under free-spinning indicates a bearing approaching failure. Pickup bearings are inexpensive to replace proactively — they are expensive to replace after they’ve damaged the shaft or housing through failure.

Knotter knife and bill hook

At 200 hours, assess knife edge and bill hook tip condition against your 50-hour inspection baseline. If the knife is showing accelerated dulling or the bill hook tip is visibly rounded, replace before the next cutting rather than waiting for the annual seasonal service.