JLG 740A, Service And Maintenance Manual

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SECTION 2 - GENERAL
2-4 – JLG Lift – 3121160
fied intervals required in the Lubrication Chart in
Section 1. Always examine filters for evidence of
metal particles.
3. Cloudy oils indicate a high moisture content which
permits organic growth, resulting in oxidation or cor-
rosion. If this condition occurs, the system must be
drained, flushed, and refilled with clean oil.
4. It is not advisable to mix oils of different brands or
types, as they may not contain the same required
additives or be of comparable viscosities. Good
grade mineral oils, with viscosities suited to the
ambient temperatures in which the machine is oper-
ating, are recommended for use.
NOTE: Metal particles may appear in the oil or filters of new
machines due to the wear-in of meshing compo-
nents.
Hydraulic Oil
1. Refer to Section 1 for recommendations for viscosity
ranges.
2. JLG recommends Mobilfluid 424 hydraulic oil, which
has an SAE viscosity of 10W-30 and a viscosity
index of 152.
NOTE: Start-up of hydraulic system with oil temperatures
below -15 degrees F (-26 degrees C) is not recom-
mended. If it is necessary to start the system in a
sub-zero environment, it will be necessary to heat
the oil with a low density, 100VAC heater to a mini-
mum temperature of -15 degrees F (-26 degrees C).
3. The only exception to the above is to drain and fill
the system with Mobil DTE 13 oil or its equivalent.
This will allow start up at temperatures down to -20
degrees F (-29 degrees C). However, use of this oil
will give poor performance at temperatures above
120 degrees F (49 degrees C). Systems using DTE
13 oil should not be operated at temperatures above
200 degrees F (94 degrees C) under any condition.
Changing Hydraulic Oil
1. Use of any of the recommended crankcase or
hydraulic oils eliminates the need for changing the
oil on a regular basis. However, filter elements must
be changed after the first 50 hours of operation and
every 300 hours thereafter. If it is necessary to
change the oil, use only those oils meeting or
exceeding the specifications appearing in this man-
ual. If unable to obtain the same type of oil supplied
with the machine, consult local supplier for assis-
tance in selecting the proper equivalent. Avoid mix-
ing petroleum and synthetic base oils. JLG
Industries recommends changing the hydraulic oil
annually.
2. Use every precaution to keep the hydraulic oil clean.
If the oil must be poured from the original container
into another, be sure to clean all possible contami-
nants from the service container. Always clean the
mesh element of the filter and replace the cartridge
any time the system oil is changed.
3. While the unit is shut down, a good preventive main-
tenance measure is to make a thorough inspection
of all hydraulic components, lines, fittings, etc., as
well as a functional check of each system, before
placing the machine back in service.
Lubrication Specifications
Specified lubricants, as recommended by the component
manufacturers, are always the best choice, however,
multi-purpose greases usually have the qualities which
meet a variety of single purpose grease requirements.
Should any question arise, regarding the use of greases in
maintenance stock, consult your local supplier for evalua-
tion. Refer to Section 1 for an explanation of the lubricant
key designations appearing in the Lubrication Chart.
2.4 CYLINDER DRIFT TEST
Maximum acceptable cylinder drift is to be measured
using the following methods.
Platform Drift
Measure the drift of the platform to the ground. Lower
booms (if equipped) slightly elevated, upper boom fully
extended with the rated load in the platform and power off.
Maximum allowable drift is 2 inches (5 cm) in 10 minutes.
If the machine does not pass this test, proceed with the
following.
Cylinder Drift
Table 2-2. Cylinder Drift
Cylinder Bore Diameter
Max. Acceptable Drift
in 10 Minutes
inches mm inches mm
3
76.2 0.026 0.66
3.5
89 0.019 0.48
4
101.6 0.015 0.38
5
127 0.009 0.22
6
152.4 0.006 0.15
7
177.8 0.005 0.13
8
203.2 0.0038 0.10
9
228.6 0.0030 0.08