Holding Valves; Description; Maintenance - Manitowoc Grove TMS700E Service And Maintenance Manual

TMS700E SERVICE MANUAL

HOLDING VALVES

Description

A bolt-on manifold style holding valve is installed on the
boom lift cylinder and a cartridge style holding valve
(Figure 2-29) in each of the two telescope cylinders. The
holding valve installed on the outlet of the cylinder provides
meter out control, will lock the cylinder in place, prevents a
load from running ahead of the oil supply, and relieves
excess pressure caused by thermal expansion.

Maintenance

Removal
Pinch Point Hazard!
Before accessing the holding valve install the telescope
hold valve tool to prevent section 3 from retracting into
section 2 when the holding valve is removed. Serious
injury may result.
1. Lower the boom to below horizontal.
2. Extend the boom to align the access holes in second
and third boom sections.
3. Install the telescope hold valve tool, P/N 80041761, see
Figure 2-28. While holding the tool in position have a
helper retract section 3 to lock the tool into place.
WARNING
Flying Object Hazard!
The holding valve can fly with explosive force if the
hydraulic pressure is not relieved. Serious injury may
result.
Grove
DANGER
Published 01-29-2015, Control # 512-01
4. From the access holes in the opposite side of the boom,
relieve the pressure in the lower telescope cylinder by
loosening the bleed plug, ( Figure 2-29).
5. Unscrew holding valve from its port block. (See
Figure 2-28 and Figure 2-39.)
Installation
1. Check the inside of the port block for any sharp edges or
burrs and remove as necessary with emery cloth.
2. Install new O-rings onto the holding valve.
3. Lubricate the holding valve and O-rings with clean
hydraulic oil.
HYDRAULIC SYSTEM
FIGURE 2-28
FIGURE 2-29
2-41
2