Cub Cadet S621 SS Operator's Manual page 15

• Replace hex bolt and tighten hex bolt to torque: 450
in. lbs. min., 600 in. lbs. max.
NOTE: To ensure safe operation of your mower, the
blade bolt must be checked periodically for correct
torque.
Drive Belt Removal & Replacement
WARNING:
and ground it against the engine to prevent
unintended starting. Drain fuel into an
approved container or place a piece of plastic
film underneath the gas cap to prevent
gasoline from leaking.
• Disconnect the spark plug wire and ground it
against the engine.
• Drain the fuel tank or place a piece of plastic
beneath the cap to prevent gasoline leakage.
• Place shift lever in the first position and tip the
mower on its side.
• Remove the center bolt which secures the blade to
the crankshaft followed by blade bell support,
blade, and blade adapter.
• Move the cutting height adjustment to the highest
position.
• Remove the three hex screws holding the baffle to
the deck and pivot baffle towards the rear of the
mower. See Figure 19.
Figure 19
• Remove hex bolt from the rear of unit holding the
transmission to the mower housing. See Figure 20.
Cutting Height
Adjustment
Figure 20
Disconnect the spark plug wire
Baffle
Hex Bolt
• Tilt the transmission forward and loosen the idler
pulley bolt and lock nut half a turn. See Figure 21.
• Using a pair of pliers, pull back and rotate belt
keeper bracket from the slot on the idler pulley.
• Slide the belt out from between the belt keeper
bracket and the idler pulley.
• Squeeze the belt together and push it forward,
while pressing the control arm inward towards the
deck and remove the six speed cable from the slot.
See Figure 21.
• Pivot the control arm down away from the pulley
and belt.
• Lift off the lower pulley assembly and remove the
old belt from around the crankshaft. See Figure 21.
Transmission
Pulley
Belt
Belt Keeper
Bracket
Idler Pulley
Bracket
Idler Pulley
Bolt and
Locknut
Six-Speed
Cable Slot
Control
Arm
Lower
Pulley Half
15
Transmission
Belt
Crankshaft
Belt
Figure 21