How to Inspect Forklift Mast Lift Chains for Wear and Damage

Forklift lift chains work every time the carriage moves up or down.

On a heavy duty forklift, they operate as part of a lifting system handling loads that may weigh many tonnes. Yet chain wear is not always obvious from the outside.

A chain does not need to be broken before it becomes a maintenance concern.

Elongation, damaged plates, corrosion, poor lubrication and uneven condition between paired chains can all indicate that the mast system needs further inspection.

That is why lift chains should be checked by condition rather than simply used until visible failure occurs.

The daily check does not need to be a detailed chain measurement.

It should begin with a visual inspection.

OSHA includes hydraulic hoses and mast chains among the items that should be visually checked before a forklift is placed into service. Forklifts in continuous use should also be examined after each shift.

Obvious warning signs can include:

• Damaged or distorted chain plates
• Heavy rust or corrosion
• Protruding or abnormal pins
• Dry chain surfaces
• Kinks or unusual chain position
• One chain appearing noticeably different from the other
• Abnormal movement or noise during lifting and lowering

If anything looks unusual, the condition should be investigated before the truck continues normal operation.

A visual inspection should remain visual.

The mast contains chains, rollers and moving sections that create serious pinch points.

OSHA specifically warns operators not to place their hands inside the mast while checking chain condition or tension.

Detailed measurements, adjustments or repairs should be performed using the correct maintenance procedure by qualified personnel.

One of the most important forms of lift-chain wear is elongation.

This does not usually mean that the chain plates simply stretch.

Wear develops around the pins and joints. A very small amount of wear at many individual joints gradually increases the total measured length of the chain.

The result may be a chain that still looks complete but has become longer than it was when new.

This is why visual inspection alone cannot determine every type of chain wear.

During a detailed inspection, a defined length of chain is measured and compared with its original or nominal dimension.

This allows the percentage of elongation to be calculated.

Renold's lifting-chain maintenance guidance gives 3% maximum elongation for forklift-truck lifting chain as one maintenance criterion.

However, that should not be treated as a universal replacement rule for every forklift.

The final wear limit should always follow the requirements of the specific forklift and chain manufacturer.

The useful lesson for operators and fleet owners is simpler:

A lift chain can reach a significant wear level before it looks close to breaking.

Wear may not be distributed evenly across the whole chain.

Some sections repeatedly articulate around sheaves while carrying load, while other sections move less frequently.

The most convenient section to inspect may therefore not be the most heavily worn section.

A periodic chain inspection should consider the working length of the chain rather than checking only one easily accessible point.

Elongation is only one possible defect.

Chain plates and pins should also be checked for signs such as:

• Cracking
• Distortion
• Side wear
• Twisting or side bow
• Protruding pins
• Abnormal impact marks

Renold specifically includes damaged or cracked plates, side-plate wear, twist, side bow and turned or protruding pins among the conditions that should be checked during lifting-chain inspection.

If a chain has experienced abnormal impact or jamming, measuring elongation alone is not enough.

The complete condition of the chain and related mast components should be checked.

Heavy duty forklifts may operate in:

• Ports
• Outdoor yards
• Coastal environments
• Humid factories
• Industrial sites with dust or contamination

These environments can accelerate chain deterioration.

Rust should therefore not always be treated as a cosmetic issue.

Severe corrosion can affect chain surfaces and joints and may also interfere with effective lubrication.

If corrosion has become significant, simply adding oil does not restore the material that has already been damaged.

Many forklift masts use two lift chains working together.

Those chains need to share the load correctly.

Warning signs may include:

• One chain appearing tighter than the other
• Uneven chain movement
• Carriage movement that does not look level
• Abnormal noise during lifting
• Clearly different wear condition between the two sides

These symptoms do not automatically mean that one chain simply needs adjustment.

The cause may also involve the chain anchors, sheaves or mast alignment.

Renold therefore includes chain adjustment and load sharing among its regular inspection points.

The chain works as part of the mast system.

When abnormal chain wear is found, related components should also be considered.

These can include:

Chain anchors
The chain needs to be securely attached and correctly positioned.

Sheaves
Wear or poor alignment can affect how the chain runs.

Mast rollers and rails
Abnormal mast movement can change how loads are distributed.

Hydraulic cylinders
The mast should raise and lower smoothly without abnormal movement or leakage.

Simply replacing a worn chain without identifying another damaged component can result in the same problem appearing again.

Normal wear develops gradually.

Impact or abnormal loading is different.

Examples may include:

• Carriage obstruction
• Chain jamming
• Mast collision
• Severe overload
• Abnormal shock loading

After an event like this, the lifting system may require additional inspection even if the chains still appear normal from a distance.

The condition of the mast, chains, anchors, sheaves and other related parts should be considered together before normal operation resumes.

It is useful to separate operator inspection from maintenance inspection.

Daily or Pre-Shift Check

The operator looks for visible defects and checks that the mast and lifting system operate normally.

OSHA requires powered industrial trucks to be examined at least daily before use, and after each shift when they are operated continuously.

Periodic Maintenance Inspection

Detailed inspection may include:

• Chain elongation measurement
• Plate and pin condition
• Lubrication
• Load sharing
• Chain anchors
• Sheaves
• Mast alignment

The interval should follow the forklift manufacturer's maintenance requirements and may need to be shorter under severe operating conditions.

A forklift working long shifts outdoors in a dusty or corrosive environment should not automatically follow the same inspection pattern as a lightly used indoor machine.

Before delivery, our heavy duty forklift testing focuses on whether the complete mast and hydraulic system operate correctly.

During testing, we check functions such as:

• Mast lifting
• Mast lowering
• Mast tilting
• Hydraulic response
• Mast stability under applicable load testing

These are part of confirming that the lifting system operates normally before shipment.

Once the forklift enters regular service, however, chain elongation, wear, lubrication and long-term condition become ongoing maintenance items at the customer's site.

Their condition will depend on actual working hours, environment, loads and maintenance practices.

This is why there is no useful universal statement such as:

"Every heavy duty forklift chain should be replaced after X hours."

Actual condition and the applicable maintenance limits matter more.

Forklift mast lift chains should not be used until they look close to failure.

Important warning signs include:

elongation, damaged plates or pins, corrosion, poor lubrication, uneven chain condition and abnormal mast movement.

Daily visual checks can identify obvious problems.

Periodic maintenance inspections are needed to identify wear that cannot be judged by appearance alone.

For a heavy duty forklift, the lift chains should always be considered together with the mast, sheaves, anchors and hydraulic system.

Finding abnormal wear early is much better than waiting for the lifting system to show a serious problem during operation.

References

OSHA - Powered Industrial Trucks: Pre-Operation Inspection.

OSHA - Sample Daily Checklists for Powered Industrial Trucks.

Renold - Lifting Chain Installation and Maintenance Manual.

Renold - Leaf Chain for Materials Handling.

Propolift - How Propolift Tests Heavy Duty Forklifts Before Delivery.

Propolift - 40 Ton Heavy Duty Forklift Load Test Before Delivery.