MacDon 9250 SP - Manual (Page 97)

Form # 46584 Issue 11/06 Web Rev_01 95
MAINTENANCE/SERVICE
Header Drive
HEADER DRIVE BELT:
PULLEY VERTICAL ALIGNMENT
Vertical misalignment of front pulley can cause a
belt failure where sections of the backing band are
missing, as shown at (T). The missing sections will
vary from 1/2 inch to 5 feet long. Failure starts with
cracks across the backing band from one side to
the other, followed by pieces falling off.
Front pulley (P) and two flat idlers must be
vertically square (90
°) to rectangular frame tube
(R) as shown.
To adjust front pulley, shim the pulley mounting
plate at both top bolts, or both bottom bolts
depending on the direction of the misalignment.
To adjust flat idlers, bend mounting arms to suit. (It
may be necessary to heat idler arms to permit
adequate bending.)
HEADER DRIVE BELT GUIDES
Improper adjustment of belt guides can cause belt
to jump one pulley groove. This will result in a belt
failure characterized by one outer portion of
backing band being frayed and separated from
one V-belt as shown at (G). The other V-belts will
still be attached to band and the band will not be
cracked through from side to side.
Belt guides for the header drive belt should be
adjusted so they do not rub belt when drive is
engaged, but still support belt when drive is
disengaged.
See adjustment details, next page.
BELT FAILURE DUE TO VERTICAL MISALIGNMENT
FRONT PULLEY & IDLERS SQUARE
TO RECTANGULAR FRAME TUBE
BELT FAILURE DUE TO JUMPING GROOVE