PRATT Industries TRUSS - Hydraulic Oil and Maintenance Schedule

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Reservoir level check
Measure oil level with the trailer hoist cylinder in the center position. The trailer must be hooked up to the
truck tractor. Remove the reservoir filler cap and inspect oil level. Use care in filling reservoir so that dirt or
other foreign material does not get into the hydraulic system. Rectangular tank - fill to two inches below flange
of reservoir. Cylinder tank - fill to four inches below flange of reservoir.
Do not overfill. Install reservoir filler cap.
There must be enough space to hold all the oil when the cylinder is retracted, with some space to allow for
expansion when the oil is hot.
Draining oil reservoir
The hydraulic oil should be changed at least once a year or sooner if it becomes contaminated. Drain the
system by removing the reservoir drain plug. Catch all oil in a suitable container. Reinstall the plug and fill
reservoir to required level with the proper type of grade of oil.
Oil recommendations
• Use AW-46 oilfor the hydraulic system.
• Detergent oils are not recommended because the additives attack the cylinder packing.
• Never use crank case draining, transmission oil, kerosene, fuel oil, water, or any non-lubricating fluids.
• Never thin oil with kerosene or fuel oil in winter operation. Either of these will cause packing to swell
resulting in plungers sticking. Good low viscosity hydraulic oils are available on the market.
Trailer maintenance schedule
Trailer maintenance services required
In addition to the pre-trip daily inspection, the services listed below are Pratt’s suggested maintenance service
interval guide for keeping your trailer in peak operating condition. These suggested service intervals will add
thousands of operating miles and many years of trouble-free service to the life of your
PRATT trailer.
SCHEDULED MAINTENANCE SERVICE
Each 5,000-Miles or Once a Month
(Whichever comes first)
• Check kingpin and upper coupler.
• Check electrical and skid control (if applicable) for proper operation.
• Check secondary and parking brake system (if applicable) for proper operation.
• Check tires and wheels. (Torque wheel nuts to proper torque).
• Check axle oil level, add oil if required.
• Check wheel seals for leaks.
• Inflate tires to proper pressure.
• Drain moisture from air reservoirs
• Check accessories operated with air from brake system.
• Inspect brake system glad hands, hoses, tubing, chamber valves, and reservoirs for leaks or damage.
• Check chamber push rod travel and adjust brakes.
• Check lining thickness.
• Visually check axle alignment.
• Inspect splashguards.
• Check tire carrier, mounting and lock chain.
• Check hydraulic system for damage or leaks.
• Inspect U-Bolts and torque to specification.