- Cylinders for leakage at the rod, fittings and welds, as well as for damage to rod and case.
- Holding valves for proper operation.
- Control valves for leaks at the fittings and between stations, and control valve linkages for wear, smoothness of operation and tightness of fasteners.
- Electrical systems for presence of dirt, moisture and frayed wires.
Every three or four months, or 300 hours of operation, whichever comes first.
- Wear pads for general condition.
- Rotation bearing for proper torque of all accessible mounting bolts.
- Base mounting bolts for proper torque.
- Crane structural components (base, stabilizers, mast, inner boom, outer boom, extensions, jib booms and extensions) for deformation, cracks and corrosion.
Yearly or every 1,200 hours, whichever comes first.
- Changing hydraulic fluid.
- Calibrating control and safety valves for correct pressure and relief valve settings.
- Checking all valves to ensure they maintain the correct settings.
- Inspecting the rotation drive system for proper backlash clearance and abnormal wear, deformation and cracks.
It’s important that service technicians follow the maintenance schedule in their manufacturer’s service manual, which is typically set by the calendar year, stresses Cook. Cranes working in high-usage environments should receive maintenance based on the number of service hours they have operated.
WIRE ROPE AND HOOK
An important part of regular crane inspection involves checking the wire rope and hook frequently, Cook says.
“There are a number of characteristics to look for in your wire rope, some requiring immediate replacement and some indicating the rope should be monitored very closely,” he says. “Corrosion might be cause for replacement and at the very least noted and carefully monitored.
Other reasons a wire rope might need to be replaced include:
- Three broken wires in one strand or a total of six broken wires.
- Flat spots on the outer wires.
- A decrease in diameter which indicates a core failure.
- Distortion, such as kinking, crushing or birdcaging (wire rope strands are forcibly untwisted and become spread outward).
Hooks also are a critical component and must be monitored closely for safety reasons, which is why they are a daily inspection item, says Cook. A deficient hook must be removed from service right away.
Hooks should be removed and repaired if any of the following conditions are present:
- Bending or twisting.
- Wear that exceeds 10 percent of the original dimension.
- Cracks, nicks or gouges.
- Deformed or malfunctioning latch.
Service/utility trucks come equipped with either a reciprocating air compressor or rotary screw air compressor. No matter which model of air compressor a truck is outfitted with, the airend (compressor screw element) oil level should be checked daily, says Cook.
Technicians should also make sure the air tanks have been drained of all condensation before using the compressor. Upon starting the unit, technicians should observe that it is building pressure and inspect the fitting and air lines for any leaks.
Oil should be changed in a compressor every 250 service hours or every three months, whichever comes first, he advises.
If all the components of a service/utility truck “are not properly maintained and serviced, the risk to technicians can be significant,” warns Cook. “Poor maintenance can lead to catastrophic failures that can threaten the safety of the technician and others working in the immediate area.
“Additionally, when your service/utility truck is down due to mechanical problems, it impacts your bottom line.”
Service truck owners are usually pretty good about keeping up on the chassis’ preventive maintenance schedule, but they’re often not as diligent about other components of the service body, such as the crane and air compressor, he notes.
A regular body maintenance program should be established to ensure that truck bodies are kept in good repair and safe operating condition, advises Rob Porter, a sales manager with Hercules...
Benefits to periodic truck body washing.