Tightening Double Sickle Drive Belts; Tightening Single Sickle Drive Belt - MacDon 912 Operator's Manual

Tightening Double Sickle Drive Belts

1. To tighten cross-shaft drive belt (G) only:
NOTE: If timing belt (L) also requires
tightening, go to step 2.
a) Loosen auger drive belt at adjuster (H).
b) Loosen four nuts (J) at driver pulley mounting
plate.
c) Turn adjusting bolt (K) clockwise until a force
of 12 lbs. (55 N) deflects belt (G) 1/8 inch (3
mm) at mid-span.
d) Tighten nuts (J) to lock the position, then
tighten auger drive belt. See "Auger Drive".
2. To tighten L/H timing belt (L):
a) Loosen auger drive belt at adjuster (H).
b) Loosen four nuts (J) and two nuts (M) at pulley
mounting plates.
c) Turn adjusting bolt (K) clockwise until a force
of 6 lbs. (28 N) deflects timing belt (L) 1/2 inch
(13 mm) at mid-span.
d) Tighten two nuts (M) to lock the timing belt
tension.
e) Tighten cross-shaft and auger drive belts as
described in steps 1 c) and 1 d).
3. To tighten R/H timing belt (P):
a) Loosen three nuts (R) at R/H driver pulley
mounting plate.
b) Turn adjusting bolt (S) clockwise until a force
of 6 lbs. (28 N) deflects timing belt (P) 1/2 inch
(13 mm) at mid-span.
c) Tighten nuts (R) to lock the position.

Tightening Single Sickle Drive Belt

IMPORTANT: To prolong belt and drive life, do not
over tighten belt. Operate at minimum tension
required to prevent slipping or excessive belt whip.
To adjust:
1. Loosen idler mounting bolt (A).
2. Use a punch or screwdriver in pry holes (B) to
raise idler until a force of 12 lbs. (55 N)
deflects belt 1/2 inch (13 mm) at mid-span.
3. Tighten bolt (A).
When installing a new belt:
1. Never pry belt over pulley.
2. Loosen bolt (A) and move idler fully down.
3. Install belt and adjust belt tension as above.
4. Re-adjust belt tension after a short run-in
period. (About 5 hours).
Form # 46620
MAINTENANCE/SERVICE
49
H
LOOSEN AUGER DRIVE BELT FIRST
L/H SICKLE DRIVE BELTS
R
S
R/H SICKLE DRIVE BELT
A
SINGLE SICKLE DRIVE BELT TENSION
P
B
Issue 11/06