Learn which plants thrive in your Hardiness Zone with our new interactive map!

How to Service a Toro 420 Lawn Mower

By Steven Douglas

Toro LX series 420 and 460 lawn and garden tractors are designed and built to last many years under normal operating conditions. The operator's manual for these models outlines a series of maintenance procedures that should be strictly followed to ensure long-term dependability and safety. These procedures are easy to follow and may be accomplished in a step-by-step manner by most operators in a few hours.

Park the tractor on a flat level surface, set the parking brake and and remove the keys. Remove the spark plug wire from the spark plug to prevent accidental starting.

Adjust the rider's seat positioning by tilting the seat forward on its front hinges, then loosening the two securing knobs located on the bottom of the seat. Slide the seat fore and aft on its runners the re-tighten the knobs once a comfortable position has been achieved.

Check the air pressure in all tires. Inflate to 10 psi for the rear tires, and 14 psi for the front tires. Do not over-inflate.

Level the mowing deck (fore and aft) so that the front of the deck is a 1/2 inch lower than the rear of the deck. If necessary, loosen the outer adjustment nut several turns on the end of the deck hanger rod located at the front end of the tractor. Raise the front of the deck by gradually tightening the inner hex nut against the front hanger bracket. Tighten the outer hex nut.

Level the mower deck (side to side) by loosening by several turns the outer adjustment nut on the end of the deck hanger rod (located at the left rear side of the tractor). Raise the left side of the deck by gradually tightening the inner hex nut against the left rear hanger bracket. Tighten the outer hex nut.

Adjust the parking brake by locating the compression spring and brake disc on the right rear of the tractor. Slightly loosen the hex nut seen on the lower right side of the brake assembly. Using a feeler gauge, adjust the gap to .011 inches between the brake puck and the disc. Re-tighten the hex nut.

Adjust the steering linkage (under the tractor) so that the tires have neither an excessive toe-in nor toe-out positioning (actual setting should be a slight 1/16 inch toe-in). Loosen the hex nut on the drag link bar. Take off the hex nut (on the top of the ball joint). Twist the ball joint toward the adjustment nut to shorten the drag link length. Replace the hex nut, then re-tighten the jam nut when correct toe-in is attained.

Change the oil and refill with 10W-30. Open the oil-drain valve (beneath the engine). Remove the oil-fill cap. Drain the used engine oil. Replace the oil-drain valve. Add approximately 2 1/2 quarts fresh oil to the oil-fill opening and replace the oil-fill cap.

Change the air filter located beneath the air cleaner cover. Loosen the air cleaner cover knob and remove the cover and old air filter. Insert a new air filter, replace the cover and tighten the knob.


Things You Will Need

  • Clean rags
  • Air pressure gauge
  • Hand air pump
  • Tape measure
  • 10W-30 engine oil
  • Replacement air filter

About the Author


Residing near the Central Florida beaches, Steven Douglas has written extensively on resolving small-business issues since 1990 in publications such as ForexFactory, Forex-Tsd, FxStreet and FxFisherman. After earning a master's degree in administration from the University of Maryland, his primary focus has been on international currency trade and how it can be effectively utilized by small businesses across the United States.