Steering Orbitrol; Description; Orbitrol Repair - Manitowoc Grove 5540F Service Manual

5540F/YB5515 SERVICE MANUAL
Symptom
Binding or poor centering of steering
wheel.
Steering orbitrol locks up.

STEERING ORBITROL

Description

General
The steering orbitrol Figure 10-16 provides directional
control and metering of oil for precise steering control. In the
neural or balance position, when the steering wheel is not
turned, the IN port (P) is connected to the OUT port (T) and
oil from the pump returns to tank Figure 10-16. Oil is locked
in the lines by the interacting spool and sleeve. Centering
springs keep the spool and sleeve in relative position. The
spool is coupled to the steering wheel and rotates inside the
sleeve when the steering wheel is turned. Corresponding
ports in the spool and sleeve align to meter oil from the pump
into the steering circuit and also allow return to tank. When
the sleeve catches up with the spool, oil flow is blocked to the
steering cylinder lines, and the available supply from the
pump is returned to tank.
Steering Left
When making a left turn, flow from the pump enters port P
Figure 10-16. The gerotor takes this flow and meters it to
port L (left turn). Return flow from the steering cylinders,
enters port R and is returned to tank through port T.
Steering Right
When making a right turn, flow from the pump enters port P
Figure 10-16. The gerotor takes this flow and meters to port
R (right turn). Return flow from the steering cylinders, enters
port L and is returned to tank through port T.
Emergency Manual Steering
The gerotor Figure 10-16 in the orbitrol permits steering, with
difficulty, when power is lost. A check valve between the IN
GROVE
Probable Cause
1. Large dirt particles can cause
binding between orbitrol spool and
sleeve.
1. Large particles of contamination in
metering section.
2. Severe wear and/or broken pin.
and OUT ports allows for recirculation of the oil to prevent
cavitation when steering without power.

Orbitrol Repair

Special Tools
A spring installation tool, is required to assemble the orbitrol.
Removal
1. Remove the outside cover plate Figure 10-15 in front of
the operator's compartment.
p0100
2. Completely clean around the area of the steering
orbitrol.
3. Put tags on the lines to the steering orbitrol for
identification at installation.
Published 10-21-2010, Control# 198-04
STEERING SYSTEM
Action
1. Clean the orbitrol. Repair or
replace if necessary. If another
component has failed, generating
contaminants, flush the hydraulic
s y s t e m w h i l e b y p a s s i n g t h e
orbitrol.
1. Clean the orbitrol. Repair or
replace if necessary.
2. Repair or replace the orbitrol.
Steering
Column
Steering
Orbitrol
FIGURE 10-15
10
10-17