HOISTS AND COUNTERWEIGHT RT880E SERVICE MANUAL
5-6 Published 11-10-2014, Control # 524-00
2. All the cable must be removed from the hoist drum to
check the fleet angle. Using mason cord or cat gut fish-
ing line you will be able to pull the line tight to make an
accurate measurement of the fleet angle. Find the cen-
terline of the hoist drum by using a square and drawing a
line horizontal on the drum. Put a line vertical to the hori-
zontal line in the absolute center of the drum by using a
tape measure. With the boom at 0 degree, tie the line
tight to the boom nose and have it in the center of the
right hand boom nose sheave.
NOTE: If this special equipment is not available, sufficient
accuracy in locating a centerline may be obtained
by using a steel square against the machine’s inner
surfaces of both flanges. It is advisable to avoid
using any cast surfaces in this procedure unless a
check from both flanges indicates that the resultant
line is straight.
3. Tie the line around the hoist drum so that the line is very
tight and the line is crossing the absolute center of the
drum at the centerline mark you put on the drum.
4. Using a protractor, lay it on the vertical line on the hoist
drum so the string line is in the center of the protractor.
The string line will be at the 90 degree mark on the pro-
tractor if the hoist is straight with the boom nose sheave.
If it is not at the 90 degree mark, the hoist mounting bolts
will have to be loosened and the hoist moved so it is.
NOTE: This test is for cable leaving gaps while spooling.
5. Elevate the boom above 45 degrees boom angle to
check if the hoist is level. Reposition the hoist drum and
tighten the cord so you can have the cord in the center of
the protractor at the 90 degree mark. If the cord is not at
the 90 degree mark, the hoist will have to be shimmed
until the cord is at the 90 degree mark.
NOTE: This test is for cable piling up on one side of the
hoist drum.
PISTON MOTOR AND CONTROL VALVE
Description
The piston motor is a bent axis, bidirectional, variable
displacement heavy-duty motor. The motor is bolted to the
hoist and is geared directly to the hoist planetary.
The motor control valve is bolted to the motor.
Maintenance
Removal
1. Thoroughly clean the external surfaces of the drum and
motor with steam or clean solvent and blow dry.
2. Tag and disconnect the hydraulic lines connected to the
hoist motor and the motor control valve.
3. Remove the capscrews and lockwashers that secures
the motor and motor control valve to the hoist.
4. Place the motor and motor control valve in a clean, dry
suitable work area.
Installation
NOTE: Care must be taken to assure the primary thrust
plate remains properly located in its counterbore
when the motor is re-installed. If the hoist is oper-
ated with the primary thrust plate wedged between
the primary gears and the planet carrier, or with a
thrust washer out of position severe damage to
internal hoist components could result.
1. Install a new O-ring on the motor pilot then lubricate with
petroleum jelly or gear oil. Engage the motor shaft with
the brake clutch inner race and lower into place.
2. Apply Loctite® No. 243 to the mounting bolts, and install
the bolts and lockwashers. Torque the bolts to 102 Nm
(75 pounds-foot).
3. Connect the hydraulic lines as tagged during removal.
4. Fill the drum with oil. Refer to Lubrication, page 9-1 in
this manual.
IDLER DRUM AND CABLE FOLLOWER
Description
The main and auxiliary hoists are equipped with an idler
drum on the forward side of the hoist. The main hoist idler
drum is used to keep the hoist cable from coming in contact
with the boom. When the crane is also equipped with an
auxiliary hoist, the idler drum on the auxiliary hoist is used to
keep the hoist cable from coming in contact with the main
hoist. The cable follower is mounted on the rear side of it’s
respective hoist. The cable follower applies a downward
spring pressure against the cable onto the hoist drum, to
ensure that the cable will be uniformly wound onto the hoist
drum, and also prevent cable from jumping under abnormal
line conditions.
CAUTION
Do not alter holes or stop blocks on the crane mounting
plate, as very small adjustments result in large angular
changes. Extreme care should be taken to avoid over-
correction.
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