JLG 15/20MSP Service Manual - Manual (Page 77)

SECTION 4 - CONTROL COMPONENTS
3121231 – JLG Lift – 4-21
4.8 PUMP-MOTOR ASSEMBLY - SERVICE
PROCEDURE
Hydraulic Pressure settings and Adjustment
Adjust system pressure so that platform will raise with
maximum rated capacity in platform.
The following pressure setting are factory recommended
(initial) settings;
Turning adjustment screw clockwise increases system
pressure, turning screw counterclockwise decreases
system pressure. (See Figure 4-6., Hydraulic Pressure
Adjustment Screw. (Machine Rear Covers Removed))
Perform pressure adjustment with oil at normal operating
temperature. If pressure is set when oil is cold, platform
may not raise rated load after soil has warmed.
Hydraulic Pressure Gauge Connection
ONLY OPEN HYDRAULIC SYSTEM LINES WITH THE MAST FULLY
LOWERED TO RELIEVE PRESSURE IN THE SYSTEM. CAREFULLY
LOOSEN REQUIRED FITTINGS, WEAR SAFETY PROTECTION
EQUIPMENT WHEN WORKING WITH HYDRAULIC SYSTEMS.
Remove the hydraulic oil filter and install a t-fitting
between the pump and the extend line to connect a
hydraulic pressure gauge as shown in Figure 4-7., Typical
Hydraulic Pressure Gauge Installation (Hydraulic Filter
Removed).
CHECK, and if necessary, ADJUST the hydraulic pressure
to initial settings shown in table at the beginning of this
section. Cycle the hydraulic system several times with the
maximum load capacity in the platform, then recheck
pressure setting. When pressure has stabilized continue
to "After Filter Pressure Check" following.
MODEL PRESSURE SETTING
15MVL/15MSP 2600 PSI
20MVL 1800 PSI
20MSP 2800 PSI
1. Remove Adjust Screw Cap 2. Pressure Adjustment Screw
Note: Machine rear covers must be removed to access pump motor.
Figure 4-6. Hydraulic Pressure Adjustment Screw.
(Machine Rear Covers Removed)
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2
1. Pressure Gauge Assembly 3. T- Fitting
2. Extend Line 4. Return Line
Figure 4-7. Typical Hydraulic Pressure Gauge
Installation (Hydraulic Filter Removed).
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3
1
4