MacDon CA25 OM - Manual (Page 138)

SECTION 8. MAINTENANCE AND SERVICING
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Revision B
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8.9.8 Sickle Drive Belts: Non-Timed Drive
This section applies to Single Knife headers,
and 40 and 45 ft. Double Knife headers.
For Double Knife headers with timed drives,
refer to Section 8.9.9 Double Knife Drive Belts:
Timed Drive.
8.9.8.1 Tension Adjustment
IMPORTANT
To prolong belt and drive life, do
NOT over-tighten belt.
CAUTION
To avoid personal injury, before servicing
machine or opening drive covers, follow
procedures in Section 8.1 PREPARATION
FOR SERVICING.
a. Open endshield.
b. Loosen two bolts (A) on sickle drive mounting
bracket.
c. Turn adjuster bolt (B) to move drive motor until
a force of 20 lbf (80 N) deflects belt (C) 3/4 in.
(18 mm) at mid-span.
d. Tighten jam nut at (B) and bolts (A) on drive
mounting bracket.
e. Re-adjust tension of a new belt after a short
run-in period (about 5 hours).
8.9.8.2 Removal
a. Loosen sickle drive belt using procedure in
previous section so that belt (C) can be slipped
off drive pulley.
b. Remove bolt in plate
(D) in endsheet at
sickle drive box, and
remove plate. This
provides clearance
between pulley and
endsheet for the belt
when it is removed.
c. Slip belt over and behind sickle drive box pulley
(E), and remove belt. Utilize the notch in pulley
to assist in removing the belt.
8.9.8.3 Installation
a. Route sickle drive belt (C) around sickle drive
box pulley (E) and sickle drive pulley (G).
Utilize the notch in the pulley to assist in
installing the belt.
NOTE
When installing new belt, never pry
belt over pulley. Be sure drive motor is
fully forward, and then tension the
belt.
b. Tighten belt. Refer to Section 8.9.8.1 Tension
Adjustment (in previous column).
c. Check clearance between belt (C) and belt
guide (F). The measurement should be 0.04 in.
(1 mm). Adjust as follows:
1. Ensure belt is properly tensioned.
2. Loosen bolts (G), and adjust position of
guide (F) as required.
3. Tighten bolts.
d. Re-install plate (D), and secure with bolt and
nut.
e. Close endshield.
A
C
B
LH SHOWN - RH OPPOSITE FOR DK
G
G
E
F
LH SHOWN - RH OPPOSITE FOR DK