McConnel PA7070T Operator's Manual page 55

HYDRAULIC SYSTEM
Oil Supply
Check the oil level in the reservoir daily.
Oil Condition & Replacement
No fixed time period can be quoted for oil changes as operating conditions can vary widely
but a visually inspection of the oil will often indicate its current overall state. Signs of a
reduction in its condition will be apparent by changes in colour and appearance when
compared to new oil. Oil in poor condition can be dark, smell rancid or burnt, or in some
cases be yellow, unclear or milky in appearance indicating the presence of air or
emulsified water. Moisture resulting from condensation can become entrapped in the oil
causing emulsification that can block the return line filter, consequentially the filter system
will be by-passed and the oil and any possible contaminants present will continue to
circulate without filtration risking damage to hydraulic components. All are indications or
conditions that will require replacement of the oil.
Hydraulic oil is a vital component of the machine; contaminated oil is the root cause of
70% of all hydraulic system failures. Contamination can be reduced by the following:
 Cleaning around the reservoir cap before removal, and keeping the tank area clean.
 Use of clean containers when replenishing the system.
 Regular servicing of the filtration system.
Filtration System
Machines are protected by both replaceable 125 micron suction strainers and low pressure
10 micron full flow return line filters – the diagram below is a 'scaled up' view illustrating
the filtering capability built into the hydraulic system of the machine:
Suction strainers
The replaceable 125 micron suction strainers (Part No. 8401097) are fitted within the
hydraulic tank and are 'screw' fitted with easy access for removal and replacement.
Return Line Filter
The 10 micron absolute filter elements (Part No. 23371.02) should be changed every 500
or annually, whichever occurs first. It is important to note hours worked as if the filter
becomes blocked an internal by-pass within the canister will operate and no symptoms of
filter malfunction will occur to jog your memory.
Tank Breather
To reduce the risk of pump cavitation it is advisable to replace the 10 micron absolute tank
breather (Part No. 8401137) on an annual basis under normal working conditions – for
machines operating in dry dusty environments it is recommended that replacement be
increased to 6 monthly.
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