A 15-minute undercarriage inspection catches the wear that schedules the next replacement: tension and sag, rollers and idlers, sprockets and chain, and the hardware between them. The routine is the same on every machine, and the findings go into one log per machine. For a Saskatchewan operator, the inspection is the cheapest tool in the maintenance budget.
Related reading: for roller diagnosis, see our roller diagnosis guide, for sprocket wear, see our sprocket wear guide, and for chain stretch, see our chain elongation guide.
What a Good Inspection Covers
A good inspection covers the whole loop in a fixed order: track condition, tension and sag, rollers and idlers, sprocket and chain, and hardware. The order keeps the check complete and the findings comparable between services.
The inspection is a measurement routine, not a visual pass: each part family gets a reading or a condition check, and the readings go in the machine log. The log is what turns the 15 minutes into a trend.
The fixed order also keeps the inspection safe: the machine is parked and blocked before the checks start, and the track is never worked on under tension. The safety step is part of the routine, not a separate one.
This page is the single-machine routine. For scheduling inspections, budgets, and spares across multiple machines, see our fleet maintenance guide.
Start With the Quick Checks: Tension, Sag, and Track Alignment
Tension and sag come first because they change the rest of the readings: check the sag against the published range, then look at the track ride on the rollers and the idler. Alignment shows as uneven contact or a track that walks to one side.
The quick checks take the first few minutes and set the context for the wear readings. A track out of tension explains wear that the parts alone would not.
Rollers and Idlers: What to Look For on the Steel Parts
Check the rollers and idlers for flats, flange wear, weeping seals, and free rotation. Each sign is a reading: a flat spot is a roller loaded hard, a weep is a seal losing, and a tight rotation is a bearing failing.
Compare left and right, because a difference between sides points to alignment or a single worn component. The comparison is the diagnostic shortcut of the steel check.
Sprockets, Chains, and Shoes
Check the sprocket teeth for hooking, the chain pitch for stretch, and the shoes for grouser and plate wear. The three read together because the chain wears the sprocket and the shoes load the chain.
Measure the chain pitch over several links and read the sprocket profile with a gauge where available. The pair's readings schedule the drive-end replacement.
The shoe check reads grouser height and plate thickness at the same service, because the shoes carry the ground load that the rest of the loop depends on. The four-part read — sprocket, chain, shoes, and the hardware between them — is what keeps the drive end on the plan.
Recording Findings and Setting Thresholds
Record the findings with the machine hours and compare them with the previous service. The trend, not the single reading, is what sets the replacement threshold.
Set the threshold before it is needed: the reading that triggers the order, the part numbers for the machine, and the delivery window. The threshold turns the inspection into a plan.
The threshold should be written on the machine log beside the readings, so the next inspection compares against the trigger as well as the limit. The written trigger is what keeps the replacement decision consistent between mechanics.
The threshold also sets the order date: when the reading approaches the trigger, the part number and the delivery window go into the plan for the next stop.
The findings should also be compared left and right, because a difference between sides points to alignment or a single worn component rather than normal service wear.
How Inspection Findings Turn Into a Replacement Plan That Holds
The inspection plan lists what to replace, when, and with which part numbers, all confirmed against the serial number. The plan is what keeps the machine to one maintenance stop instead of a series of failures.
For a fleet, the same log serves every machine: the readings, the thresholds, and the orders in one place. The log is the fleet's undercarriage memory.
| 15-minute check | What to record |
|---|---|
| Track tension and sag | Sag reading against the range |
| Track ride and alignment | Centred or walking, left vs right |
| Rollers and idlers | Flats, flange wear, seals, rotation |
| Sprocket and chain | Tooth profile, chain pitch |
| Shoes | Grouser height, plate thickness |
| Hardware | Loose bolts, rust, missing parts |
Conclusion
A 15-minute undercarriage inspection covers the loop in a fixed order, records the findings in the machine log, and sets the replacement threshold from the trend. The routine is the same on every machine, and the log is what keeps the plan honest.
Key Takeaways for Canadian Operators
- Run the checks in a fixed order so readings stay comparable.
- Measure the parts; do not rely on a visual pass alone.
- Record findings with hours and set the thresholds early.
- Keep one inspection log per machine for the fleet.
Frequently Asked Questions
How often should the undercarriage be inspected?
At every service, and more often on abrasive, wet, or high-travel duty. The 15-minute routine is short enough to run with the regular service.
What tools does the inspection need?
A tape for sag and track measurement, a gauge or caliper for flange and grouser readings, and a wrench check for hardware. The same tools at every service keep the readings comparable.
How do I know when a reading means replacement?
Compare the reading with the machine's published limit and with the previous service trend. The threshold is reached when the trend approaches the limit, not when the part fails.