Skytrak 6042 Service Manual User Manual download pdf (Page 300)

Hydraulic System

8.68

Model 6042 Legacy Origin 7/02

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 Unloader Valve

The unloader valve (Fig. 8-34, 1) creates system pressure

and distributes the hydraulic fluid for various vehicle

functions via its load sense, bypass to tank (via the oil

cooler), and primary and secondary valve ports. The

unloader valve is secured to the frame toward the front of

the vehicle near the main control valve (2).

Figure 8-34 The Unloader Valve

DO NOT loosen, disassemble or attempt to adjust any

cartridges unless specifically instructed by OmniQuip to

do so! Tampering with the cartridges will irrevocably alter

pressure in the affected circuits.

a. Unloader 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 Tag Usage.”

3. Temporarily block up or support the raised boom.

4. Unlock and open the rear door. Allow the hydraulic

fluid to cool.

5. At the unloader valve (Fig. 8-35, 1), label, disconnect

and cap the hydraulic lines (2). Remove the 12 hex-

head capscrews (3 and 11), 12 lockwashers (4), six

flange halves (5) and three o-rings (6).

Note: The check valve manifold (Fig. 8-35, 10) is secured

to the unloader valve by the hex-head capscrews (11)

attaching the hose and flange halves.

6. Remove the check valve manifold (Fig. 8-35, 10)

from the unloader valve (1).

7. Remove the three hex-head capscrews (Fig. 8-35, 7),

three lockwashers (8) and three washers (9) securing

the unloader valve (1) to the vehicle frame. Remove the

valve (1) from the vehicle. Wipe up any hydraulic fluid

spillage.

Figure 8-35 Unloader Valve Removal

MA10,0220

Front

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.

WARNING: Escaping hydraulic fluid

under pressure can penetrate the skin, causing

death or serious injury. Relieve hydraulic pressure

before servicing any hydraulic component.

LSG

VG

MA7140

1 2 ... 295 296 297 298 299 300 301 302 303 304 305 ... 543 544

Comments to this Manuals

No comments

Skytrak 6042 Service Manual User Manual Page 300

Comments to this Manuals

Related products and manuals for Special machinery Skytrak 6042 Service Manual