SkyTrak 8042 Service Manual - Manual (Page 491)

Hydraulic System
8.76 Model 8042, 10042, 10054 Legacy Rev. 10/03
8.12 VALVES AND MANIFOLDS
Valves are devices that open or close passageways.
Manifolds contain circuit passageways involved in the
distribution of hydraulic fluid flowing under pressure.
There are various valves and manifolds in use on this
vehicle. As valves open and close, hydraulic fluid is
directed to flow through various passageways to the
prescribed circuit, causing vehicle functions to occur.
8.12.1 Main Control Valve
The main control valve (1) is mounted on the frame under
the lower transmission cover.
The main control valve assembly (2) consists of various
working sections with their own valve assemblies, each
providing a specific hydraulic function. The section
assemblies are the outlet (3), lift/lower (4), extend/retract
(5), mid-inlet/outlet (6), frame sway (7), attachment tilt (8),
auxiliary hydraulics (9) and load sense outlet (10)
sections.
Note: If the vehicle has auxiliary hydraulics installed, the
auxiliary hydraulics section will have relief valves (11). If the
vehicle does not have auxiliary hydraulics installed, the
relief valve ports will be plugged.
a. Main Control Valve Removal
1. Park the vehicle on a firm, level surface, fully retract
the boom, raise the boom, place the travel select
lever in (N) NEUTRAL, place the neutral lock lever in
the (N) NEUTRAL LOCK position, engage the park
brake switch and shut the engine OFF.
2. Place an Accident Prevention Tag on both the
ignition key switch and the steering wheel, stating
that the vehicle should not be operated. Refer to
Section 1.5, “Accident Prevention Tags.”
3. Temporarily block up or support the raised boom.
4. Unlock and open the rear door. Allow the hydraulic
fluid to cool.
MH3750
Front
1
WARNING:
DO NOT get under a raised
boom unless the boom is blocked up. Always
block the boom before doing any servicing that
requires the boom to be up. Unexpected lowering
of the boom may cause death or serious injury.
WARNING:
Hot hydraulic fluid can
cause severe burns. Wait for hydraulic fluid to
cool before servicing any hydraulic component.
MH3350
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