Walker MC (20 HP) Owner's Manual

Also see for MC (20 HP): Illustrated parts manual

Contents

Walker MC (20 HP) Owner's Manual Manual pdf 72 page image

68Maintenance Instructions REPLACING/REPAIRINGPTO Shear PinThe PTO drive shaft connection to the deck gearboxhas a shear pin to provide shock load protection tothe mower deck drive. This system provides pri-mary shock protection in case of blade impact andwill normally shear before the individual shear boltson the blade hub.When the PTO pin has sheared, use the followingprocedure to replace it:1. Loosen the two bolts securing the PTO shaftguard on the deck; lift the guard off. (Holes inguard are slotted for easy removal.)2. Rotate U-joint on shaft to align the shear pinhole with the hole (and shear pin fragment) inthe shaft. Use a punch to drive the remainingportion of the old shear pin out.3. Install new shear pin and secure with cotter pin.U-JointShaft AssemblyU-JointTube AssemblyCotter PinShear PinSplit Spring Pin(Retains U-Joint Held on Shaftwith Broken Shear Pin)PTO Shear PinIMPORTANT: Use only Walker P/N 8067-13shear pins for replacement to provide propershock protection -- these pins are hardened toshear under a specific amount of load.4. Reinstall the PTO shaft guard.Before operating the deck, inspect the blade over-load shear bolts and also check blade timing (ongear driven decks) by moving blades through one(1) complete revolution. Make sure blade tipspass clear of each other. If timing is incorrect, con-tact your Walker dealer.NOTE: Use Walker P/N 8067-10 for heavy dutygearboxes.Mower BladesMower blades are removed and remounted as de-scribed in Sharpen Mower Blades instructions.During the course of sharpening and inspectingmower blades, if there are any of the followingconditions of wear or damage, blades should bereplaced for reasons of safety and performance ofthe machine:• An excessive amount of the flat section of theblade has been ground away (removed) when theblade is sharpened. Replace the blade when lessthan a 3/4 in. (19 mm) flat section remains at theblade tip.• Examine ends of the blade carefully, especiallythe intersection where the flat section of the bladeturns up to form the “wing tip” (refer to Mower BladeProfile for Sharpening illustration in SharpenMower Blades instructions). Since sand and abra-sive material can wear metal away in this area, theblade should be replaced when metal thicknesshas worn to 1/16 in. (1.6 mm) or less.DANGERWhen blades are operated over sandysoil, and if blades are allowed to wear, a“slot” may be worn into the wing tip ofblade. Eventually a piece of the blademay break off creating a serious potentialfor injury or damage.• Check the blades for straightness by markingblade tip position inside the deck housing and thenrotating the opposite end of the blade to the sameposition and comparing. If the difference in blade tiptrack is more than 1/8 in. (3 mm), the blade is bentand should be replaced.• Inspect the blade surface, especially in formedareas, for cracks. Replace the blade if any cracksare found.WARNINGDO NOT try to straighten a blade that isbent. NEVER weld a broken or crackedblade. ALWAYS replace with a new bladeto assure safety.