Hydraulic excavators concentrate their fatigue damage in a small number of places: the boom foot, the boom-to-stick joint, the stick tip and the slew ring mounting. Cracks in those locations grow under every dig cycle and are routinely hidden by paint, mud and repair welds. An excavator inspection is built around finding them early.
We inspect excavators from compact machines to large mining shovels, with the scope adjusted to size, hours and application — including machines used for object handling, where the quick hitch and lifting configuration bring additional requirements.
Inspection checklist areas
- Boom and stick structure
- MT of boom foot, boom nose, stick heel and bucket linkage welds; visual check for box-section buckling, prior repair plates and paint cracking indicating movement.
- Pins, bushes and bores
- Pin retention, bore ovality and bush wear at boom foot, boom-to-stick and bucket pivots; UT of pins where end access permits.
- Slew ring and upper frame
- Slew bearing clearance, slew ring bolt torque and condition, upper frame and counterweight mounting welds.
- Quick hitch and attachments
- Hitch locking mechanism, secondary retention, warning devices and attachment pin wear per Safe Work Australia excavator quick hitch guidance; bucket and tooth condition.
- Hydraulic system
- Cylinder rod scoring and seal leakage, hose abrasion and routing, boom lowering control and hose burst protection where fitted, accumulator condition.
- Undercarriage
- Track link, pin and bush wear, roller and idler condition, sprocket wear, track frame welds and final drive leaks.
- Operator protection and access
- ROPS/FOPS identification and condition, cab mounts, seat and restraint, access steps and handrails, emergency egress, mirrors and cameras.
Known failure modes
Boom foot fatigue cracking
Toe cracks in the welds joining the boom foot casting or box section to the boom side plates, driven by bending and slew loads on every cycle.
Stick heel and bucket linkage cracking
Cracks at the H-link and bucket cylinder mount welds, aggravated by rock-face prying and heavy attachments.
Slew ring bolt failure
Progressive bolt loosening or fatigue leading to slew bearing separation; often preceded by measurable bearing clearance increase.
Quick hitch attachment release
Loss of bucket or attachment due to worn locking components, disabled secondary retention or incompatible pins.
Uncontrolled boom lowering
Hose or fitting failure on the boom cylinder circuit without load-holding protection.
Applicable standards and regulations
| Reference | Title | Relevance |
|---|---|---|
| AS 2294.1 / ISO 3471 and ISO 3449 | Earth-moving machinery — Protective structures (ROPS and FOPS) | Identification, condition and modification checks on the operator protective structure. |
| ISO 10567 | Earth-moving machinery — Hydraulic excavators — Lift capacity | Basis for assessing rated object-handling capacity and load charts where the excavator is used for lifting. |
| Safe Work Australia — Excavator quick hitch guidance | Guidance on quick hitches for excavators | Expectations for locking, secondary retention and warning systems on quick hitches. |
| AS/NZS 1554.5 | Welding of steel structures subject to high levels of fatigue loading | Acceptance criteria for repair welds on boom, stick and frame. |
| AS/NZS 4024 series | Safety of machinery | Guarding of fans, belts and slew area. |
| NSW MDG 15 | Mobile and transportable plant for use at mines | Design and maintenance expectations referenced on mine sites for excavators and their attachments. |
When to inspect
- Introduction to a new mine or quarry site
- Structural inspection at OEM or site hour intervals, typically every 2,000 to 5,000 hours for high-duty machines
- After any boom, stick or frame repair weld
- Before fitting a new quick hitch or heavier attachment
- Reported cracking, oil leaks at pins, or unusual slew noise
Frequently asked questions
Where do excavators usually crack?
At the boom foot welds, the boom nose and stick heel joint, the bucket cylinder and H-link mounts, and around the slew ring mounting on the upper frame. These areas are examined with magnetic particle testing after paint removal at the weld toes.
Do you inspect the quick hitch?
Yes. The hitch locking mechanism, secondary retention, wear on the hitch and attachment pins, and the in-cab warning system are inspected against the manufacturer's requirements and Safe Work Australia guidance, because attachment release is one of the most common excavator incidents.
Can an excavator be certified for lifting?
Excavators used for object handling need a rated capacity chart based on ISO 10567, an object-handling configuration (load-holding valves, overload warning where required) and a defined lifting point. The inspection confirms those elements are present and functional, and identifies any that are missing.
How long does an excavator inspection take on site?
A structural and compliance inspection of a 30 to 90 tonne class machine with NDT of critical welds typically takes a day with the machine cleaned and isolated. Larger mining shovels are scoped individually.