JLG M4069 Service Manual - Manual (Page 24)

SECTION 2 - GENERAL
2-4 – JLG Lift– 3121824
2.3 LUBRICATION AND INFORMATION
Hydraulic System
1. The primary enemy of a hydraulic system is contam-
ination. Contaminants enter the system by various
means, e.g., using inadequate hydraulic oil, allowing
moisture, grease, filings, sealing components, sand,
etc., to enter when performing maintenance, or by
permitting the pump to cavitate due to insufficient
system warm-up or leaks in the pump supply (suc-
tion) lines.
2. The design and manufacturing tolerances of the
component working parts are very close, therefore,
even the smallest amount of dirt or foreign matter
entering a system can cause wear or damage to the
components and generally results in faulty opera-
tion. Every precaution must be taken to keep
hydraulic oil clean, including reserve oil in storage.
Hydraulic system filters should be checked,
cleaned, and/or replaced as necessary, at the speci-
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 -26° C (-15° F) is not recommended. If it is
necessary to start the system in a sub-zero environ-
ment, it will be necessary to heat the oil with a low
density, 100VAC heater to a minimum temperature of
-26° C (-15° F).
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 -29°
C (-20° F). However, use of this oil will give poor per-
formance at temperatures above 49° C (120° F). Sys-
tems using DTE 13 oil should not be operated at
temperatures above 94° C (200° F) under any condi-
tion.
Changing Hydraulic Oil
1. Use of any of the recommended hydraulic oils elim-
inates 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 specifi-
cations appearing in this manual. If unable to obtain
the same type of oil supplied with the machine, con-
sult local supplier for assistance in selecting the
proper equivalent. Avoid mixing petroleum and syn-
thetic base oils. JLG Industries recommends chang-
ing 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.