Walker MDD (20.9 HP) - Manual (Page 82)

78
Maintenance Instructions
ADJUSTMENTS
Blade Clutch (PTO)
Clutch Disengagement/Brake Action
The declutched or disengaged position of the
blade clutch idler pulley is adjustable and is set to
give belt release without excessive slack and to
apply the blade brake. The blade brake is activated
by linkage to the clutch idler pulley mechanism. The
brake is designed to stop the blades within five (5)
seconds after disengaging the clutch.
Use the following procedure to check and adjust
clutch disengagement and brake action:
1. Use the adjustment nut on the brake band (refer
to PTO Clutch Disengagement Adjustment
illustration) to set the position of the clutch idler
pulley in the declutched position. Adjust the
declutched pulley position to give 1/2 in.
(13 mm) pulley travel from “clutch engaged”
to “clutch disengaged.” To check and adjust the
pulley travel, first engage the clutch, then mea-
sure the distance the pulley moves down as the
clutch is disengaged.
2. After the pulley travel is set, check blade brake
action as described in CHECKING/SERVICING
the Blade Brake Action in this section. If the
brake does not stop the blades within five (5)
seconds, check the following:
a. Check clearance between the clutch idler
pulley and the motor mount when the pulley
is in the declutched position. If there is no
clearance and the idler pulley rests on the
frame, the blade brake will not be applied
when the clutch is disengaged. Normally,
this problem would be caused by a short
engine PTO drive belt. Change the belt
(refer to REPLACING/REPAIRING the
Drive Belts in this section), and readjust
pulley travel as described by step 1 (above).
PTO Clutch Disengagement Adjustment
b. Check both the brake band and brake
drum on the drive pulley for wear. Replace
worn brake parts and readjust pulley travel
as described by step 1 (above).
Clutch Engagement/Belt Tension
The clutch engagement and PTO belt tension are
adjusted using the clutch actuator rod. Initially, after
installing a new PTO belt, after 10 hours and every
100 hours thereafter, check and adjust for the three
dimensions in the clutch linkage as shown.
Adjust the bolt head clearance [1/4 to 3/8 in. (6 to 10
mm)] first, then adjust spring length. If adjustments
are needed more frequently than 100 hours to main-
tain the linkage dimensions, it may suggest prob-
lems with pulley wear or belt misalignment.
WARNING
It is important to check and maintain
blade brake action for safe operation of
the machine.
Brake Band
Adjustment Nut
1/2 in.
(13 mm) Clutch
Idler Pulley
Engine Pulley
PTO Drive
Pulley