Maintenance - Strong GR4 Procedures Manual

Hydraulic System

(Maintenance)

The hydraulic system must be kept free of dirt. Inside the tank is a strainer mounted on the pump suction
line. If it becomes clogged, the pump will malfunction due to starvation. Also, damage to the pump will
occur if starvation continues. Any increase in the noise of the system, while no load applied. May
indicate this condition. This strainer should be checked after the first 100 hours and thereafter every six-
(6) months or anytime a hydraulic component is replaced. To service the strainer, unbolt and gently lift
the cover plate from the tank. This cover is directly over the strainer in the bottom of the tank. The
strainer is connected to the suction line with pipe threads, turn it counterclockwise several turns and it will
come out. Rinse the strainer in a nonflammable cleaning fluid using a paint brush to loosen sludge on the
screen. If the screen shows any breaks, replace.
Suction line threaded connections must be maintained airtight. Use semi-head Permatex, Teflon tape or
other oil proof compound. Keep compounds out of line. Teflon tape is preferred since it will not damage
the hydraulic system.
Approximately 30-60 gallons of hydraulic oil, Mobile DTE 10 the same as used in original installation,
should be maintained in the reservoir. (Tank size determined by final drive configuration.) The tank is
equipped with an oil level indicator. Never allow the oil level to be less than the "low" mark of the sight
gauge mounted at the end or side of the hydraulic tank.
Overheating of oil will occur if storage level drops too low. Condition and color of oil should be
checked. Change oil when considerably darker than new oil. Also, check oil temperature occasionally.
It should not be more than 150 degrees Fahrenheit during last half of workday. A thermometer is part of
the hydraulic sight gauge. One hundred thirty (130) degrees is uncomfortable to touch. Oil dangerously
hot is too hot too touch.
All hoses should be checked periodically for signs of failure. It is very important to keep close check on
the pump suction hose. Check for soft spots or breaks. The oil used in the system is Mobile DTE 10.
The hydraulic system is composed of either one or two independent circuits. (A circuit diagram is
enclosed). One circuit provides oil for the mixer motor drive, bucket drive, bucket tilt and material hose
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