SECTION IV
PREVENTIVE MAINTENANCE
If the brakes require adjustment, proceed as follows (see
CAUTION
Figure 4-11): 1. Raise the wheels off the ground using
Be sure the machine is level, and the
the outriggers.
boom is in the boom rest before
checking the oil in the winch.
2. Push in the locking sleeve on the slack adjuster, and
turn the adjusting screw until the stroke required to apply
CHECK HOSES AND TUBING
the brakes is reduced to one inch.
Carefully inspect all hoses and tubing on the machine
for leaks and/or damage. Leaks that cannot be stopped
3. Check the adjustment by making several brake
by tightening the fitting should be removed and repaired
applications. The air chamber push rod should move a
or replaced.
total of one inch from the released to the applied
position.
CHECK WINCH OIL LEVELS
Two makes of hydraulic winches have been used on
4. Release the brakes and spin the wheel, by hand, to
this machine. Earlier machines were equipped with free-
be sure the brake shoes are not dragging.
fall and non free-fall type Gearmatic Winches, while later
machines are equipped with P&H Winches.
The lining to drum clearance of the front brakes should
be checked, using a feeler gauge. If the clearance is
To check the winch oil levels in a P&H Winch, proceed
more than 0.060" (1.5 mm), adjust the brakes manually
as follows (see Figure 4-12): 1. Remove the cover over
as described below, and schedule the vehicle for brake
the winch brake. Then remove the oil level plug and
service.
relief valve. Pour oil, of the type specified in Section III
for the Sprag clutch, into the relief valve opening until the
1. Jack or hoist the front wheels off the ground.
oil just runs out of the oil level opening. Replace the oil
level plug and relief valve.
2. Remove the dust cover from the adjusting slots above
and below the brake chambers.
3. The adjusting bolts have right hand treads. Using an
adjusting spoon, turn the star wheel until a heavy drag is
developed, then back off the star wheel to a very light
drag on the drum. Reinstall the dust covers in the
adjusting slots.
Figure 4-11. Adjusting Positive Slack Adjusters
1-4-11
