SkyTrak 6036 Service Manual - Manual (Page 303)

8.87 Model 6036 Legacy
Hydraulic System
8.12.3 Secondary Function Manifold
The secondary function manifold (Fig. 8-49, 1) is a
directional control valve. Hydraulic oil from the unloader
valve flows into the secondary function manifold where the
pressure is reduced before the oil is directed to the power
steering unit or the park brake.
The secondary function manifold is a machined block with
ports for two pressure-reducing valves, a pressure relief
valve, two park brake solenoid valves (one normally open
and one normally closed), a check valve and diagnostic test
nipples. The secondary function manifold is secured on the
left side of the frame (Fig. 8-49, 2) with two carriage bolts
and two hex flange nuts.
Figure 8-49 Secondary Function Manifold Location
Verify the correct operation of the solenoids before
considering replacement of the secondary function manifold.
Refer to Section 9, “Electrical System.”
The manifold itself
is not serviceable and must be replaced if defective.
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 irrevocably
alter pressure in the affected circuits.
a. Secondary Function Manifold Replacement
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. Label or otherwise mark the hydraulic hoses in
relation to the secondary function manifold.
Disconnect and cap all hoses, fittings, solenoid wire
terminal leads, etc.
6. Remove the secondary function manifold from the
vehicle. Wipe up any hydraulic fluid spillage in, on,
near and around the vehicle.
MA8300
Front
1
2
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.