John Deere JD450 Service Manual — Wiring Diagrams

Check steering lever free travel before you pull anything apart. On manual steering it should be 1-1/4 to 1-1/2 inches at the top of the handle, per the specs on page 371; power steering runs 1-1/2 to 2 inches. Back off brakes that self-adjusted tight, then retest both levers under load.

Drain and inspect the fuel filters first, then crack the injection lines at the nozzles and bleed air until fuel runs clean. Replace the in-line filter on gasoline units every 500 hours as noted on page 153, or every 1000 hours with the Airtex transfer pump. Check tank vent and pickup screen.

Replace the ruptured hose, then refill and bleed the loader circuit before cycling anything under load. Run the machine until oil reaches the normal 150 to 180 degrees F range listed on page 516, then check relief pressure against the 2250 psi loader spec on page 13. Clean the suction screen.

Measure sag in the center of the track between rear sprocket and carrier roller: page 389 calls for 7/8 to 1-1/8 inch. Never use a grease gun rated above 8000 psi on the adjuster. Check track shoe bolt tightness and pin wear before buying new rails.

Free up the speed control linkage and check every pivot for binding before you condemn the pump. Work through the governor section starting on page 127, then inspect the injection pump flex ring. If you open the pump, torque the advance hole plug to 70-80 in-lbs on Model C units.

Pull the final drive and set flanged axle end play to 0.002 to 0.005 inch with the slotted nut, as page 364 spells out. Torque the pinion shaft quill cap screws to 85 ft-lbs and the final drive housing bolts to 170 ft-lbs. Replace both seals, not just the leaker.