JLG sky trak mmv Service Manual page 414

Hydraulic System
3. Inspect internal passageways and parts for wear,
damage, etc. If inner surfaces of the pilot select
manifold DO NOT display an ultra-smooth, polished
finish, or are damaged in any way, replace the
manifold in its entirety. Often, dirty hydraulic fluid
causes failure of internal seals and damage to the
polished surfaces within the component.
Note: ALWAYS replace seals, o-rings, gaskets, etc. with
new parts to help ensure proper sealing and operation.
Lubricate seals and o-rings with clean hydraulic oil.
4. Inspect the solenoid cartridges for proper operation.
Check by shifting the spool to ensure that it is
functioning properly. Check that the spring is intact.
Inspect the cartridge interior for contamination.
5. Install the cartridges (4). Torque to 35-40 lb/ft
(47-54 Nm) Install the coils (3) and solenoid nuts (2).
Torque the nuts to 4-6 lb/ft (5-8 Nm). DO NOT
overtighten.
Front
9.116
c. Pilot Select Manifold Installation
1. Place the pilot select manifold (5) into position on the
valve plate (6) in the rear of the vehicle.
2. Install the two lockwashers (7), capscrews (8) and
nuts (9) securing the manifold (5) to the main control
valve plate bracket (10).
3. Prime the pilot select manifold by adding a small
quantity of fresh, filtered hydraulic oil, from a clean
container, in the port holes before attaching the tubes.
4. Use new oiled o-rings as required. Reattach and
secure all tubes, clamps, wire terminals, etc.
2
5. Check the routing of all hoses, wiring and tubing for
sharp bends or interference with any rotating
3
members, and install tie wraps and/or protective
conduit as required. Tighten all tube clamps.
4
1
6. Start the engine and run at approximately 1/3-1/2
throttle for about one minute without moving the
vehicle or operating any hydraulic functions.
MM3680
7. Inspect for leaks and check the level of the hydraulic
fluid in the reservoir. Shut the engine OFF.
5
6
9
WARNING:
Avoid prolonged engine
operation in closed areas with inadequate ven-
tilation. Failure to properly ventilate exhaust
fumes can result in death or serious injury.
WARNING:
Hydraulic oil leaking
under pressure can penetrate the skin and
cause severe personal injury. DO NOT use
your hand or any part of your body to check for
hydraulic leaks. When checking for hydraulic
leaks, wear safety glasses and gloves to help
provide protection from spraying hydraulic oil.
Use a piece of cardboard or paper to search
for leaks.
8
7
10
MT2880
Model MMV Rev. 12/04