Outrigger Control Valves; Optional Equipment; Pintle Hook; Secondary Front Steer (Ce Option) - Manitowoc Grove RT880E Service And Maintenance Manual

UNDERCARRIAGE
a. If oil stops flowing, the cylinder's internal piston seal
is sealing properly.
b. If oil continues to flow out the rod port, the cylinder's
internal piston seal is leaking.
3. After determining the condition of the cylinders internal
piston seal, leave the rod side hose disconnected and
continue to test the pilot operated check valve.
Testing Pilot Operated Check Valve For Leakage
1. Fully extend and set the outriggers.
CAUTION
When performing step number 2, remove hose to adapter
connection slowly. Trapped pressure may exit between
the outrigger cylinder and the work port pilot operated
check valves in the outrigger selector valve.
2. Remove the piston side cylinder hose from the sus-
pected leaking jack cylinder (see Figure 8-36). Oil will
flow until the cavity in the cylinder port block empties.
Once the port block cavity empties, oil should stop flow-
ing from the piston side port.
a. If oil stops flowing, the cylinder's pilot operated
check valve is sealing properly.
b. If oil continues to flow out the piston port, the
cylinder's pilot operated check valve is leaking.
If oil flow is not noticed from either port, the cylinder and pilot
operated check valve are functioning properly, and any
cylinder contraction during normal operation can be
attributed to thermal contraction of the oil.

Outrigger Control Valves

Description
There are four valve assemblies responsible for controlling
the outrigger system, the integrated outrigger/rear steer
valve, the front and rear outrigger control manifolds, and the
pilot operated check valves.
NOTE: For a more detailed description and maintenance
of the valves, refer to Valves, page 2-31.
Pilot Operated Check Valve
The pilot operated check valves are located in the outrigger
jack cylinder port blocks. The check valve provides two
8-38
functions; the first function is a holding valve, the second
function provides a thermal relief of the jack cylinder.
Integrated Outrigger/Rear Steer Valve
The integrated outrigger/rear steer valve is mounted on the
rear face of the carrier frame front cross member. The
outrigger portion of the valve consists of a 4-way two position
solenoid valve. The inlet section contains the main relief
valve.
Outrigger Control Manifold
The front and rear outrigger control manifolds are located
on the respective outrigger boxes. Each manifold consists of
four 12 volt solenoid valves and an assembly mounting kit.

OPTIONAL EQUIPMENT

This section is provided to give a brief description of the
optional equipment available for the crane which is not
discussed elsewhere within this service manual.

Pintle Hook

A conventional pintle hook with safety pinned latch can be
installed on the front and/or back of the crane. It is bolted
onto a plate which is welded onto the front or rear outrigger
boxes of the crane.

Secondary Front Steer (CE Option)

A secondary front steering system for the CE option consists
of a hydraulic pump, load sense steer priority flow divider
valve (part of the swing directional control valve), load sense
steering control valve, two steer cylinders, dual accumulator
charge valve, pressure switches, pilot operated valve and
two accumulators.
The hydraulic pump is driven by the engine and supplies
hydraulic flow to the load sense steering priority flow divider.
The load sense steer priority flow divider valve provides flow
to the load sense steering control valve. When the steering
wheel is turned, the load sense steering control valve sends
a load sense signal to the load sense steer priority flow
divider. As the load sense pressure increases, the priority
flow divider spool shifts to direct oil from the hydraulic pump
to the steering control valve, and to direct oil from the L port
and R port of the steering control valve to the front steer
cylinders.
The two accumulators allow for emergency steering should
there be a loss of hydraulic pressure.
Published 11-10-2014, Control # 524-00
RT880E SERVICE MANUAL