Used Excavator Boom and Stick Inspection Guide: Cracks, Welds and Structural Repairs

A used excavator can start, travel and dig normally while still carrying expensive structural damage. The boom and stick handle repeated bending, shock and twisting loads, so a careful inspection must look beyond fresh paint. Buyers should examine the steel, welds, pins and alignment before agreeing to a remote purchase or arranging export.

Start With a Clean, Well-Lit Walk-Around

Ask the seller to park the excavator on level ground with the attachment safely lowered. Dirt and heavy grease can hide fine cracks, while strong direct glare can make weld repairs difficult to see. Request close-up photos and a slow video from both sides of the boom and stick, including the upper and lower surfaces.

Pay special attention to high-stress areas: boom foot mounts, cylinder brackets, pin bosses, the boom-to-stick joint, lifting eyes, reinforcement plates and the stick-to-bucket connection. These areas repeatedly transfer digging force through the structure.

How to Recognize Cracks and Previous Repairs

A crack often begins beside a weld toe, around a pin boss or at the end of a reinforcement plate. Look for a narrow dark line, rust bleeding through paint, repeated paint splitting, or grease collecting along one short path. A clean repair is not automatically unacceptable, but its quality and history matter.

Warning signs include uneven weld beads, excessive grinding, plates added only on one side, mismatched paint texture, heat discoloration, and a repair that stops abruptly in a stressed area. Ask when the repair was completed, why it was needed and whether the structure was checked for alignment afterward.

Check Boom and Stick Alignment

Stand in front of and behind the machine from a safe distance. The boom, stick and bucket linkage should appear centered rather than leaning or twisting. Compare the gaps around both sides of the joints. Unequal gaps, a bucket that sits visibly off-line, or hydraulic cylinders that do not track squarely can indicate wear, bent steel or an earlier impact.

Operate the boom and stick slowly through their normal range. Watch the joint movement and listen for sharp knocks. Movement should be smooth without the structure shifting sideways before the attachment begins to move.

Inspect Pins, Bushings and Bosses

Structural condition and joint wear must be evaluated together. Excessive play can increase shock loading and accelerate cracking around the bosses. Ask for a video showing the operator lifting the attachment slightly and changing direction while the camera focuses on each joint. Visible delay or side movement deserves closer measurement.

Check whether retaining hardware is present, grease reaches both sides of the joint, and the boss edges remain round rather than elongated. Heavy grease alone does not prove good maintenance; it may have been applied immediately before inspection.

Review Cylinders, Hoses and Mounting Points

Inspect cylinder rods for scoring, rust and oil film. Examine the cylinder mounting brackets for cracks and repaired welds. Hoses should not rub against sharp steel edges when the boom and stick move. Any hose routing change after a structural repair should be checked through the full working range.

Remote Inspection Evidence to Request

• Wide photos of both sides of the complete attachment.
• Close-ups of every pin boss, cylinder bracket and reinforcement plate.
• A slow video showing boom and stick movement from idle.
• A joint-play video with the camera kept steady near each pin.
• Unpainted or cleaned close-ups of any suspicious weld or crack line.
• Measurements or professional inspection when structural condition is uncertain.

Why Structural Inspection Matters Before Export

Once a machine is loaded and shipped, verifying the cause and extent of a crack becomes more difficult and expensive. Structural repair may also require qualified welding, alignment checks and new pins or bushings. A clear inspection record helps the buyer compare machines on real condition instead of paint appearance alone.

Use our used excavator inspection checklist for the complete machine, and review the excavator shipping guide from China before planning transport.

Request Machine Details

YCHS can provide current machine photos, operating videos and export information for available used construction equipment. Contact our sales team on WhatsApp: +8618017348066 or +8615300859658.