Commonly Overlooked Annual Inspection Items on Bucket Trucks and Digger Derricks

Owners of bucket trucks and digger derricks are responsible for ensuring their equipment is inspected annually. While safety is the foremost concern, annual inspections can also reveal small operational issues before they cause serious, and possibly expensive, equipment repairs.

According to factory-trained technicians at Terex Service Centers, the following are some of the most frequently overlooked inspection items, listed in increasing order of seriousness. Most of them apply to either digger derricks or aerial devices, while the last two are specific to aerials.

Missing Safety or Operational Decals:

Operational and Safety decals provide valuable information to the users. Sometimes it’s not obvious what’s missing from the equipment if you don’t know what decals are supposed to be there. It’s especially important to make sure hand signal charts aren’t missing from digger derricks. Hand signals provide a means to communicate between the operator and ground personnel when they are in a noisy environment. Failure to communicate clearly could lead to possible injury or equipment damage and could result in an OSHA violation.

Hydraulic Oil Levels not maintained and Hydraulic Filters Not Replaced:

Oil levels must be checked according to the manufacturer’s recommendations for equipment to operate as designed. More frequent checks based on operating and weather conditions may be necessary.

• Low levels, if left unattended, could lead to expensive, unplanned repairs. Burning up one pump can easily be a $2000 repair, not to mention a loss in productivity from the equipment being out of service.
• High levels can also cause issues. Checking the fill level when the outriggers are extended can often lead to over filling, which leaves no room for expansion and can contribute to oil leakage.

A dirty oil filter can lead to accelerated wear and damage to pumps, cylinders, hydraulic valves and hoses due to the fact the filter is no longer capturing harmful contaminants and particles circulating in the fluid.

Damaged Winch Rope:

In addition to the daily visual inspection, the full length of the winch rope should be unspooled and inspected hand-over-hand during the annual inspection. When you feel cuts or a bulge, an indication of internal rope damage that can be caused by shock loading or kinking, the rope should be replaced. Additional inspection and replacement criteria are available from the rope manufacturers.

Rotation Bearing Bolts Not Torqued:

While the process is simple, this is one of those items that cannot be overlooked. It may be easier to inspect and re-torque bolts with two people—one to rotate the bearing and the other to check the bolt torque. Information on the proper bolt torque and lubricant is available in the operator’s manual. For more information on how to check the torque on rotation bearing fasteners, click here.

Too Loose Bearing Deflection/Backlash:

Checking the amount of allowable play in the rotation bearing takes time and a proper understanding of how to measure it. If there is too much play, this may be an indication that the rotation bearing could be worn and needs to be replaced. It could also be an indication that the boom has been shock loaded. For more information on how to conduct a Rotation Bearing Deflection Test for Terex equipment, see Tech Tip 4.

Leveling Chain has too much/too little Play:

Leveling systems on aerial devices should have specific amounts of preload. Too much or too little tension increases wear and possible damage. Checking leveling tension requires taking the boom cover off. Failure to keep the chain within tolerance could affect the self-leveling of the bucket as the boom moves through its range of motion.

Bucket and Liner Damage:

Cracks, gouges and damage to the aerial device bucket could affect the structural integrity and contribute to reducing dielectric strength. Tools can get dropped, which damages the liner and the bucket itself. It’s important to look underneath, inside, and out of the bucket by removing the liner.

Annual inspections are a task to be performed by qualified people, such as Terex Utilities’ factory trained technicians who have access to the right tools to do the job correctly. For those owners who perform annual inspections in-house, Terex offers several training programs designed to provide technicians with the knowledge to become a qualified inspector: click here.