Use Preventive Maintenance to Stop Recurring Failures

Sept. 28, 2010

It's no secret history repeats itself, but that doesn't have to be the case when it comes to equipment downtime. One sure way to put a stop to recurring failures before they become catastrophic is by compiling and using the accumulative data found in preventive maintenance (PM) histories.

At Cajun Equipment Services, President Michael Bates uses PM histories to protect his 145-unit fleet by preventing failures through high-quality maintenance practices, protecting the resale value of those assets, and avoiding premature equipment failure.

"We look for recurring failures or leading indicators of major failures so we can schedule the machine out of service rather than waiting for the machine to schedule itself out of service," he says.

According to Bates, the key to preventing premature equipment failure is the shop technician.

"A lot of companies use oil and other fluid analysis," he says. "We don't, unless it's required to maintain the OEM warranty. We rely on the technician to spot leading indicators visually, indicators such as the condition of the fluid. Technicians look for water and dirt contamination, metal, and discoloration. If any one indicator throws up a red flag, we go to the next level to find out what the specific contaminant is and how it got there. Is it a seal failure? Do we have someone in the field putting contaminated fluids in the machine? Is there equipment with a fluid leak at a jobsite that is being topped off incorrectly?"

Because Bates only uses oil and other fluid analysis to maintain warranty, the company doesn't track or store that data.

"The lab keeps all our records," he says. "We take the oil sample and send it to the lab; the lab sends the results to our dealer to maintain the warranty. We don't track it.

"We have an advantage over some other companies in that, typically, no one touches our equipment but us and the dealer. In both cases, the technicians are skilled enough to recognize a leading indicator and take corrective action."

The basic principles of PM are the same throughout the fleet; although, there is a slight difference in how PM is done when it comes to machine type. For example, says Bates, PM for a wheel loader is going to be different from a crawler dozer.

"You have tracks to maintain on dozers or excavators that you don't have on a wheel loader, so PM will vary somewhat," he says. "But the principles of using a PM schedule to avoid catastrophic failure are the same."

Accumulating PM history data is just the first step.

"You can have a truck load of data, but if you don't interpret and apply your data, and make it part of your real-world PM program, it's useless," says Bates. "It's just another function that burns up time and energy. We keep historical data on our machines from cradle to grave, and we keep it by categories that include type of machine and type of failure."

Historical data allows the company to track the failures that can occur at specific intervals.

"That gives us a crystal ball," says Bates. "For example, we know that out of 25 wheel loaders that had the same number of hours on them last year, we had to replace two torque converters. Of course, you can always have an unexpected failure, but as a rule, the more data you retain over a longer period of time the better you can identify trends and manage the assets."

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Mike St. Clair, Caterpillar
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Abnormal oil samples are illustrated on this chart provided by CJ Miller. The chart also identifies conditions such as wear, viscosity, water, metal and dirt.