JLG 4017 Service Manual - Manual (Page 113)

8.13 4017
Hydraulic System
f. Main Control Valve Installation
1. Loosely install the four main control valve mounting
bolts through bracket on the inside frame rail of the
engine bay.
2. Install the main control valve onto the bracket,
aligning the bolts with the holes in the end sections
of the main control valve. Slide the main control
valve into position, and tighten all bolts.
3. Prime the main control valve by filling the inlet
openings with fresh, filtered hydraulic oil from a
clean container, before attaching the hoses.
4. Use new oiled o-rings as required. Uncap and
connect all hoses, clamps, etc. to the main control
valve.
5. Check the routing of all hoses, wiring and tubing for
sharp bends or interference with any rotating
members, and install tie wraps and/or protective
conduit as required. Tighten all tube and hose
clamps.
6. Connect the positive (+) and negative (-) battery
cables to the battery terminals and remove the
battery.
7. Start the engine and run at approximately one-third
to one-half throttle for about one minute without
moving the machine or operating any hydraulic
functions.
8. Inspect for leaks and check the level of the hydraulic
fluid in the reservoir. Shut the engine OFF.
9. Wipe up any hydraulic fluid spillage in, on, near and
around the machine, work area and tools.
10. Close and secure engine cover.
g. Main Control Valve Test
Conduct a pressure check of the hydraulic system in its
entirety. Adjust pressure(s) as required. Refer to Section
8.4.1, “Hydraulic Pressures.”
8.7.2 Service Brake Valve
The service brake valve (2) is secured with four
capscrews and lockwashers at the lower left dash.
The service brakes themselves are part of the axles (the park
brake is part of the front axle only). Refer to Section 5.3, “Axle
Assemblies,” for further information.
a. Service Brake Valve Removal
1. Park the machine on a firm, level surface, lower
boom, place the transmission control lever in (N)
NEUTRAL, engage the park brake and shut the
engine OFF.
2. Place an Accident Prevention Tag on both the
ignition key switch and the steering wheel, stating
that the machine should not be operated.
3. Open the engine cover. Allow the system fluids to
cool.
4. Remove the lower dash panel.
5. Label or otherwise mark the hydraulic hoses on the
side of the service brake valve. Disconnect and cap
all hoses, fittings, etc.
6. Disconnect the pin holding the yoke to the brake
pedal arm.
7. Remove the four capscrews, four nuts and four
lockwashers mounting the service brake valve to the
steering column support.
Note: DO NOT disassemble the service brake valve.
The service brake valve is not serviceable and must be
replaced in its entirety, if defective.
MZ0330
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