Bush Hog MP5 - Manual (Page 15)

4-5 BLADE REPLACEMENT
Always replace all (4) blades on an assembly to
retain balance. In addition to replacing blades when
they become worn and dull, they should also be
replaced if the uplift angle on the trailing side of the
blade becomes worn off. As the angle wears down,
the mulching action deteriorates.
A. Raise cutter using tractor hydraulic system
and use transport locks before changing blades.
B. Turn off tractor,set parking brake and remove
key.
C. Remove bolt and Belleville washer securing
bottom blade to spindle. Remove blade. Shaft wash-
er will come off with the blade. (Figure 4-4)
D. Remove the four 3/8” x 1” capscrews and
belleville washers from the upper mulching assembly.
Remove mulching assembly. The blade bushing will
come off with the mulching assembly.
WEAR HEAVY WORK GLOVES TO PRO-
TECT HANDS FROM SHARP EDGES.
WHEN TURNING BLADES, BE AWARE OF
OPPOSITE BLADE APPROACHING.
CAUTION
E. Remove the 3/8” - 24UNF x 7/8” Gr. 8 blade-
bolt and nut for each blade. Inspect the blade nut
shoulder and the blade bolts for wear. Replace if
necessary.
F. When installing new blades on the mulching
assembly, make sure that two blades are installed
on the top side of the assembly 180° from each
other and two on the bottom side of the assembly.
The blades must mount on the rotation “pads” for
proper operation. Assemble the (4) new blades to
the blade holder using the blade nuts, bolts, and flat-
wahsers. Tighten the bolts to 45 ft./lbs. Strike the
blade nut with a heavy hammer to seat, then tighten
again.
G. Insert the blade bushing in the center of the
mulching assembly so that the bushing flange is on
the top side of the assembly. Slide the mulching
assembly and flanged bushing over the spindle shaft
and secure mulching assembly to the upper blade
carrier using the (4) 3/8” - 16UNC x 3/4 Gr. 5 bolts
and belleville washers. Torque all (4) mulching
assembly attaching bolts to 31 ft./lbs.
H. Install the blade washer over the spindle
shaft. Install the bottom blade and torque the 1/2” -
20UNF Gr. 8 bolt to 76 ft./lbs. Note: The concave
side of the belleville washer must be toward the
blades. Do not substitute with a flat washer.
14
Figure 4-4 MP 6 Blade Arrangement
3/8” - 24UNF x 7/8” Gr. 8 Blade Bolt & Blade Nut
Upper Blade Assembly
3/8” x 1” Capscrew &
Belleville Washer
Shaft Washer Bottom Blade Bolt &
Belleville Washer
Rotation Pad