Komatsu PC600 Excavator - High concentration of dirt entry, high wear rate of final drive

Affected Component: Engine
Industry Sector: Quarry & Aggregates
Machine: Quarry & Aggregates Komatsu PC600 Excavator
Critical Report: High concentration of dirt entry, high wear rate of final drive


Findings from our tests

Given the industry that the customer operated in, it was common practice to have the all machine’s undertake regular oil samples to ensure proper maintenance of machines. In one of the scheduled oil samples, large traces of lead and copper when the oil sample was analysed using Komatsu’s ICP analysis and Particle Quantifier (PQ).

Below is the comparison of sample results at 2997 hours, 3247 hours, 3510 hours and 3780 hours which returned extremely high levels of iron, lead and copper.  
Note: the final oil sample was taken the machine had already failed.

Elements Iron (Fe)   Lead (Pb) Copper (Cu)  Aluminium (Al)  Chrome (Cr)  Silicon (Si)  Sodium (Natrium Na)  Particle Quantifier (PQ) 
 3701 hours  186  92 109 5 4 16 <1 49 
 3510 hour  30 10 103 4 2 10 3 13
 3247 hours  18 6 20 3 1 4 <1 10
 2997 hours  33 25 51 <1 3 5 2 13

Alert levers at Sample
3701 hours: Critical: Extremely high levels of Iron, Copper and Lead. 
3510 hours: Action: Lead and Copper levels indicate possible bearing wear.
3247 hours: Query: Lead and Copper levels decreased, possibly to due an oil change. Customer asked whether any repairs had been carried out?
2997 hours: Caution: Lead and Copper levels indicate possible bearing wear.

What did that mean for the customer?

At the regular 3000-hour service internal, the Komatsu CMS team began noticing an unusual trend of lead and copper being present in the sample. At this stage, the alert status on the report was CAUTION which indicated an increased trend that should be monitored by the customer.

At the next service internal, the customer continued to sample the PC600’s oil which still recorded traces of lead and copper however, the count was reduced and therefore was queried by Komatsu CMS, whether any maintenance had been carried out eg a recent oil changed.

The following oil sample which the customer undertook at 3,510 hours saw a significant increase in both lead and copper since the previous oil sample. Immediately, this required urgent attention as soon as possible by the customer and was given the alert status of ACTION. The unusually high trend of both lead and copper signified bearing wear which needed to be inspected immediately, otherwise the customer could face significant downtime and costly repairs to other machine components.

Unfortunately, no action was taken by the customer as the machine continued to operate at full capacity. The operator only stopped when they actually heard metal-on-metal contact. At this point the pistons were hitting the cylinder heads as the bearings had failed.

Unfortunately, the recommendations to inspect the machine immediately was avoided, and as a result, the PC600 had failed at 3,701 hours. At this stage, the customer could no longer operate the PC600 and was forced to move the excavator into service. The unplanned downtime resulted in low productivity and significantly high maintenance costs.


Communication with the customer

At 3,510-hour service interval, the oil sample returned unusually high amounts of lead and copper when compared to the previous sample results.

The indication of possible bearing wear was reported to the customer by phone and in the sample report. The sample was also uploaded onto the website to allow ease of access should the customer wanted to review it again at a later stage.

Komatsu provides immediate assistance to minimise downtime

As the machine had failed, the Komatsu CMS team contacted the local service branch to explain the situation. The Komatsu service branch manager made direct contact with the customer and the discussion resulted in scheduling a Komatsu service technician to assist with the repair.

The Komatsu service arrived with the Komatsu genuine replacement parts and was able to successfully complete the job. The At the end of the repair, a Condition Report was completed which was provided to the customer.

For peace of mind, another oil sample was taken after the service repair which did not detect anything unusual. As the machine had returned to normal, the PC600 was once again fully operational.