Manitowoc Grove RT770E, Service Maintenance Manual

Page: 287 / 357

8-11
RT770E UNDERCARRIAGE
8
Published 11/26/2014, Control # 447-05
GROVE
Removal
1. Tag and disconnect the hydraulic lines from the steer
cylinder. Cap or plug all openings.
2. Remove the capscrew, flatwasher, and lockwasher
securing each pin weld in the rod end and barrel end of
the cylinder.
3. Remove both pin welds and two thrust washers (rod end
only), and remove the cylinder from the axle.
Installation
1. Position the cylinder onto the attachment fittings on the
axle and install both pin welds. On the rod end, install a
thrust washer top an bottom of lug.
2. Secure each pin weld with the capscrew, flatwasher, and
lockwasher. Torque capscrews; refer to
Fasteners and
Torque Values , page 1-16 for proper torque value.
3. Connect the hydraulic lines to the cylinder as tagged
during removal.
4. Operate the steering system and check the cylinder for
proper operation and any leakage.
REAR AXLE OSCILLATION LOCKOUT
SYSTEM
Description
The rear axle oscillation system Figure 8-11 and Figure 8-12
consists of two lockout cylinders, a lockout valve, and an
angle encoder. The lockout cylinders are mounted between
a cradle (fifth wheel) and the carrier frame. The lockout valve
is mounted on the left inner center frame rail and
hydraulically controls the oscillating abilities of the lockout
cylinders. The angle encoder is located in the electrical
swivel assembly.
Theory Of Operation
The rear axle is mounted on a cradle (fifth wheel) allowing
maximum oscillation of 5.9 in (15 cm) total while traveling
over uneven terrain. Oscillation is provided only when the
superstructure is within ±2 degrees left or right of directly
over the front. When the superstructure is within ±2 degrees
left or right of directly over the front, the RCL sends a CAN
bus message to the Crane Control System to allow axle
oscillation. When the Crane Control System receives this
message it switches ON a digital output thus energizing the
axle oscillation solenoids. When the solenoids are
energized, the valve spools are shifted to allow hydraulic
transfer between the two lockout cylinders. As one side of
the axle is forced up by traveling over uneven terrain, the
hydraulic oil flows from the rod end of cylinder A to the barrel
end of cylinder B and from the rod end of cylinder B to the
barrel end of cylinder A. The system is not pressurized and
oil is moved from one cylinder to the other by the action of
the axle moving the cylinder.
When the superstructure is more than ±2 degrees left or right
of directly over the front, the Crane Control System switches
OFF the digital output thus de-energizing the axle oscillation
solenoids. This de-energizes the solenoids on the lockout
valve and allows the springs in the valve to shift the valve
spools to the closed position to prevent hydraulic oil flow
between the cylinders. By stopping the flow of oil, a hydraulic
lock is created and the axle is held rigid in that position.
Pivot Point
Pivot Point
Oscillation Lockout
Cylinder
Carrier Frame
Fifth Wheel
B
A
FIGURE 8-11