JLG 723A Service Manual - Manual (Page 94)

Hydraulic System
8-12 L2906H, 2906H, 3507H, 619A, 723A, 29.6LP, 29.6, 35.7
8.8 HYDRAULIC RESERVOIR
The hydraulic reservoir and fuel tank are part of the
frame. For this reason, neither tank can be removed. For
cleaning instructions, see Section 7.7.2, “Fuel/Hydraulic
Oil Tank.”
Occasionally, oil may seep, leak or be more forcefully
expelled from the filter head when system pressure
exceeds the rating of the filter head or filler cap. If the
return filter becomes plugged, return hydraulic oil will
bypass the filter when pressure reaches 1,5 bar (22 psi)
and return to the reservoir unfiltered.
Carefully examine oil seepage or leaks from the hydraulic
reservoir to determine the exact cause. Clean the
reservoir and note where any seepage occurs.
Leaks from a cracked or damaged reservoir require that
the reservoir be flushed completely with water and
repaired by a certified welder using approved techniques.
If these conditions cannot be met, the reservoir must be
replaced in its entirety. Contact the local JLG dealer
should reservoir welding be required.
8.8.1 Pressurized Hydraulic Oil Fill Cap
The fill cap will allow the hydraulic oil reservoir to
pressurize to 0,14 bar (2 psi). Inspect the condition of the
cap seal to maintain proper reservoir pressure.
8.8.2 Hydraulic Oil Reservoir Draining
1. Park the machine on a firm, level surface, fully
retract the boom, support the boom, place the
transmission control lever in (N) NEUTRAL, engage
the park brake and shut the engine OFF.
2. Place a Do Not Operate 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 drain plug at the bottom of the hydraulic
oil reservoir.
5. Transfer the used hydraulic oil into a suitable,
covered container, and label as "Used Oil". Dispose
of used oil at an approved recycling facility. Clean
and reinstall the drain plug.
6. Wipe up any spilled hydraulic oil.
8.8.3 Hydraulic Oil Reservoir Filling
1. Be sure the reservoir is clean and free of all debris.
2. Install new hydraulic oil filters.
3. Fill the reservoir with hydraulic oil. Refer to Section
2.4, “Fluids, Lubricants and Capacities.”
4. Start the machine. Run engine to normal operating
temperature. Operate all hydraulic functions.
5. Close and secure the engine cover.
6. Remove the Do Not Operate Tags from both the
ignition key switch and the steering wheel.
8.9 IMPLEMENT PUMP (PISTON OR
GEAR)
8.9.1 Implement Pump Replacement
a. Implement Pump Removal
1. Park the machine on a firm, level surface, fully retract
the boom, support the boom, place the transmission
control lever in (N) NEUTRAL, engage the park brake
and shut the engine OFF.
2. Place a Do Not Operate 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. Properly disconnect the battery.
5. Drain the hydraulic oil reservoir. Refer to Section
8.8.2, “Hydraulic Oil Reservoir Draining.”
6. Thoroughly clean the pump (1) and surrounding
area, including all hoses and fittings before
proceeding.
MZ5510
1
PISTON PUMP SHOWN