MacDon D1 Series - Checking and Tensioning Timed Double-Knife Drive Belts

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8.6.2 Checking and Tensioning Timed Double-Knife Drive Belts
The procedure for tensioning timed knife drive belts is the same for both sides of the header. The illustrations show the
left side of the header.
DANGER
To avoid bodily injury or death from unexpected startup of machine, always stop the engine and remove the key before
making adjustments to the machine.
IMPORTANT:
To prolong belt and drive life, do NOT overtighten belt.
IMPORTANT:
Do NOT use the adjuster bolt at the drive pulley to adjust timing belt tension.
1. Shut down the engine, and remove the key from the ignition.
2. Open the endshield.
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A
Figure 8.9: Knife Drive – Left Side
3. Check drive belt tension. A properly tensioned belt (A)
should deflect 13 mm (1/2 in.) at the midpoint of the upper
span when a force of 27 N (6 lbf) is applied.
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B
D
C
A
A
Figure 8.10: Knife Drive – Left Side
4. If the belt needs to be tensioned, loosen two nuts (A) on
knife drive belt idler bracket (B).
5. Position pry bar (C) under the idler bracket, and push the
bracket upwards until a force of 27 N (6 lbf) deflects the
belt 13 mm (1/2 in.) at the midpoint of the upper span.
IMPORTANT:
Protect the machine’s paint by placing a piece of wood (D)
under pry bar (C).
PERFORMING PREDELIVERY CHECKS