All Terrain Crane Inspection Guide: What to Check Before You Buy

This guide walks through every system to inspect, in order. Bring it with you and work through it item by item. If something does not pass, you have leverage to negotiate or a reason to walk away.

If you have not read our used all terrain crane buying guide yet, start there. This article goes deeper on the inspection step.

Before You Start

A few ground rules. Once this crane is yours, it has to meet the same inspection standards OSHA holds every jobsite to. Inspect it now with that bar in mind. OSHA’s crane and derrick inspection standard (opens in a new tab) spells out what a shift, monthly, and annual inspection has to cover, and it is a good checklist to hold a used machine to before you buy it, not just after.

System 1: Carrier and Crane Engines

Start here. An all terrain crane runs on two separate engines, one in the carrier and one in the upper works, and each one needs its own check. A seller who only shows you records for one engine is only telling you half the story.

Carrier engine, cold

• Pull the dipstick. Clean oil is amber or light brown; dark, milky, or gritty oil is a problem.
• Check the coolant reservoir for oil contamination and the air filter for neglect.
• Walk the tires for even wear, cracking, and correct tread depth across all axles.
• Check axle and steering linkage for play, and look underneath for fluid on the ground.

Crane engine, cold

• Repeat the same oil, coolant, and hose checks on the upper engine.
• Look at the engine compartment for oil residue, which points to a slow leak the seller may not have disclosed.

Both engines running

• Start each engine cold and idle 5 to 10 minutes. Light grey smoke on startup is normal and should clear within a minute.
• Black smoke means incomplete combustion. Blue smoke means the engine is burning oil.
• Listen for knocking on both engines. Light valve tick is normal; deep knocking is not.
• Drive the carrier forward and backward on flat ground. Pulling to one side suggests a drivetrain or steering problem.

System 2: Hydraulic System

Hydraulic repairs are one of the most common major expenses on a used crane, and many problems show up before you start the engine.

Machine off

• Look for oil on the ground, hoses, the pump compartment, and every cylinder.
• Check the fluid through the sight glass. Clean fluid is amber or light brown; dark, burnt, or milky fluid is a problem.
• Rub fluid between your fingers. Grit or metal particles mean internal wear.
• Inspect hoses for cracks, bulges, dry rot, or chafing against the frame or boom.

Machine running

• Telescope the boom out and hold it under load for two to three minutes. A boom that drifts back in has failing cylinder seals.
• Extend and retract the outrigger cylinders and watch for smooth, even movement on all four corners.
• Cycle every function and listen for whining, knocking, or sluggishness under load.
• Watch for new leaks once the system is fully pressurized.

System 3: Boom Sections

The boom is a telescoping structure made of multiple nested sections, and it takes the most visible abuse on any crane.

Structural inspection

• Walk every boom section for bent panels, dents, and paint cracking, which often signals a bend underneath.
• Look down the length of the boom from the side for bellying, a slight bow that means the boom has been overloaded at some point.
• Check the wear pads between sections. Worn or missing pads let sections rattle and wear the structure faster.
• Extend and retract the full boom slowly and confirm each section moves in sync. A section that lags or binds points to a wear pad or cylinder problem.

Cylinder and pin inspection

• Look at the exposed chrome on the telescoping and luffing cylinders. It should be clean and shiny, with no pitting or scoring.
• Check boom base pins for play by having someone lift and lower the boom slightly while you watch the pin connections.

System 4: Outriggers and Counterweights

Outriggers are what let an all terrain crane set up safely off the carrier’s tires, and counterweights are what let it lift rated capacity. Both need to work exactly as the load chart assumes.

Outriggers

• Extend all four outriggers fully and confirm each one locks in place. A cylinder that will not hold under load is a serious problem.
• Check outrigger pads and float pads for cracks and warping.
• Look at the beams and housings for strain cracks, especially near the pin connections.
• Confirm the outrigger position indicator in the cab matches what you see outside. The load moment indicator relies on this reading.

Counterweights

• Check that counterweight sections lift, lock, and release cleanly.
• Inspect locking pins for wear and confirm they seat fully.
• Ask the seller to confirm the current counterweight configuration matches what the load chart in the cab expects.

System 5: Wire Rope and Rigging Hardware

Wire rope carries the load, and it is one of the few components on a crane with a hard, published rejection standard rather than a judgment call. OSHA’s wire rope inspection standard (opens in a new tab) lays out exactly how many broken wires or strand breaks take a rope out of service, and it is worth holding a used crane’s rope to that same line before you buy.

What to inspect

• Run the rope through your gloved hand and look for broken wires, kinks, birdcaging, and flattened or crushed spots.
• Check for corrosion or a dry, rusty look, which means the rope has not been lubricated on schedule.
• Inspect the hook for cracks, a bent throat, and a latch that closes and locks every time.
• Check sheaves and the block for smooth rotation and no wobble.
• Ask when the rope was last replaced and whether records exist. Wire rope has a service life, not just a condition.

System 6: Load Moment Indicator

The load moment indicator, or LMI, is the system that tells the operator how close the crane is to tipping or overloading. It is unique to cranes and it has to work correctly every time.

How to check it

• Power on the system and confirm it displays the crane’s current configuration correctly: boom length, angle, and outrigger position.
• Test the anti-two-block device by raising the hook block toward the boom tip. It should stop the hoist function and sound an alarm before contact.
• Watch for a functioning boom angle and boom length readout as you extend and raise the boom.
• Ask for the last calibration date. LMIs drift out of calibration over time and need periodic recalibration to stay accurate.

When to Bring a Professional

If you are not comfortable evaluating these systems, or the crane’s value justifies it, hire a certified third-party crane inspector. A professional pre-purchase inspection on an all terrain crane typically runs $800 to $2,500, more than an inspection on smaller equipment, because it usually includes a full load test and a certified inspector’s time. It can surface what is easy to miss without tools or certification: a proper load test at rated capacity, wire rope rejection criteria measured to spec, LMI calibration accuracy, and a detailed look at the annual inspection paperwork.

The cost of an inspection is almost always less than the first surprise repair, and on a machine this expensive, that gap can be large.

Red Flags That Should Stop the Deal

Some findings are reasons to walk away unless the price reflects the problem clearly:

Once you are satisfied with what you found, you know what to look for. PayDirt lists used all terrain crane inventory, with financing options available through Equify Financial. And if you still need it, our used all terrain crane buying guide covers machine history, sourcing, and financing in more depth.