Accumulator Charge Valve - JLG sky trak mmv Service Manual

9.12.10

Accumulator Charge Valve

Hydraulic oil from the rear pump flows into the accumulator
charge valve and then is directed to the power steering unit,
the two accumulators which direct pressure to the service
brakes. Oil also flows from the accumulator charge valve to
the unloader valve and the secondary function manifold.
The accumulator charge valve (9) is a machined block with
ports for various valves, cartridges and other fittings. The
accumulator charge valve is located under the engine
hood and mounted to a bracket behind and above the
main pump (10).
10
DO NOT loosen, disassemble or attempt to adjust any of
the pressure valves unless specifically instructed by
JLG to do so! Tampering with a pressure valve will irre-
vocably alter pressure in the affected circuits.
a. Accumulator Charge Valve Replacement
1. Park the vehicle on a firm, level surface, fully retract
all hydraulic cylinders, ground the attachment (if
any), 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.
Model MMV Rev. 12/04
9
MM4450
2. Place an Accident Prevention Tag on both the
ignition switch and the steering wheel, stating that
the vehicle should not be operated. Refer to Section
1.5, Accident Prevention Tag Usage .
WARNING:
cause severe burns. Wait for hydraulic fluid to
cool before servicing any hydraulic component.
3. Unlatch and open the engine cover. Allow the
hydraulic fluid to cool.
WARNING:
under pressure can penetrate the skin, causing
death or serious injury. Relieve hydraulic pres-
sure before servicing any hydraulic component.
4. With the engine OFF, relieve the hydraulic pressure
from the accumulators. Apply the service brake
pedal and then release. Do this several times until all
hydraulic pressure has been relieved from the
accumulators.
5. Label or otherwise mark the hydraulic hoses in
relation to the accumulator charge valve. Disconnect
and cap all hoses and fittings. Label or mark any
wire harness connectors as they relate to the
accumulator charge valve.
6. Remove the accumulator charge valve from the
vehicle. The accumulator charge valve (9) is held to
the mounting bracket (11) with four capscrews(12)
and four lockwashers(13) from the underside. Wipe
up any hydraulic fluid spillage in, on, near and
around the vehicle.
Hydraulic System
Hot hydraulic fluid can
Escaping hydraulic fluid
11
13
12
MM5000
9.129