Belt Replacement - MTD 690 Operator's Manual

To properly sharpen the cutting blades, remove equal
amounts of metal from both ends of the blades along
the cutting edges, parallel to the trailing edge, at a 25 °
to 30 ° angle. See Figure 29.
IMPORTANT: If the cutting edge of the blade has already
been sharpened to within 5/8" of the wind wing radius,
or if any metal separation is present, replace the blades
with new ones. See Figure 29.
It is important that each cutting blade edge be ground
equally to maintain proper blade balance. A poorly
balanced blade will cause excessive vibration and may
cause damage to the tractor and result in personal
injury.
The blade can be tested by balancing it on a round
shaft screwdriver. Grind metal from the heavy side until
it balances evenly.
When replacing the blade, be sure to install the blade
with the side of the blade marked "Bottom" (or with a
part number stamped in it) facing the ground when the
mower is in the operating position.
IMPORTANT: Use a torque wrench to tighten the blade
spindle hex flange nut to between 70 foot-pounds and
90 foot-pounds.
BeltReplacement
WARNING: Shut the engine off, remove
ignition key, set the parking brake, disconnect
the spark plug wire(s) and ground against the
engine to prevent unintended starting before
replacing belts.
For performing service on your tractor and in order to
properly mount some (separately available)
attachments, it may be necessary to remove the
tractor's cutting deck. To due so, proceed as follows:
Deck Belt (38- and 42-inch Decks)
WARNING: Shut the engine off, remove
ignition key, set the parking brake, disconnect
the spark plug wire(s) and ground against the
engine to prevent unintended starting before
removing the cutting deck.
,_ WARNING: Always wear safety glasses or
safety goggles to protect your eyes while
removing the cutting deck.
• Remove the cutting deck from the tractor (Refer to
Cutting DeckRemoval on page 22, for detailed
instructions).
• Remove the belt guards (located over each spindle
pulley) by removing the self-tapping screws which
secure them in place. See Figure 30.
• Remove and replace the belt, reassemble following
the instructions in reverse order.
/
Worn Blade Edge
Blade Separation
Sharpen Edge Evenly
Figure 29
Wind Wing
Self-Tapping
Screws
42-inch deck Shown
O
Belt Guards
Figure 30
Rear Deck Hangers
Stabilizer Bracket
Figure 31
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