Walker MDD Owner's Manual

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Contents

Maintenance Instructions REPLACING/REPAIRING71PTO 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 prima-ry shock protection in case of blade impact and willnormally shear before the individual shear bolts onthe 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.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.Mower BladesMower blades are removed and remounted as de-scribed in Sharpen Mower Blades instructions (re-fer to CHECKING/SERVICING in this section).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 CHECKING/SERVICING for Mower Blade Profile for Sharpen-ing illustration in Sharpen Mower Blades instruc-tions). Since sand and abrasive material can wearmetal away in this area, the blade should be re-placed when metal thickness has worn to 1/16 in.(1.6 mm) or less.• 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 formed ar-eas, for cracks. Replace the blade if any cracks arefound.Cotter PinU-JointTube AssemblyShear PinSplit Spring PinU-JointShaft AssemblyDANGERWhen 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 blade maybreak off creating a serious potential forinjury or damage.WARNINGDO NOT try to straighten a blade that isbent. NEVER weld a broken or crackedblade. ALWAYS replace with a new bladeto assure safety.