PM inspections are intended to identify problem areas and prevent premature failure caused from conditions such as lube fittings that aren't taking grease, lines that are worn, frayed and exposed electric lines, leaking fluids, and any part that is broken or worn out. They should be viewed as part of the overall maintenance program.
The foundation of a successful PM inspection program rests on dual cornerstones: consideration of manufacturer's recommended service intervals and a thorough understanding of the daily operating conditions of the machines. Equipment operating conditions include jobsite conditions, temperature ranges in which the unit works, and whether or not the unit is being used continuously.
"PM inspection programs vary by description from place to place," says Levi Dungan, CEM, owner of Dungan & Co. Dungan writes equipment appraisals. "It could be something as mundane as a daily operator inspection or something as detailed as a periodic inspection by trained technicians."
Although inspection programs can start with OEM recommendations, Dungan says the fleet professional needs to customize his approach. For example, there are differences in a program that is set up based on hours and a program based on fuel consumption.
"The hours-based program doesn't take into account how hard the machine has been working," he says. "Yet an hours-based approach is probably easier to maintain. It also more accurately reflects most equipment manufacturers' recommendations."
A consumption-based program is a more accurate representation of how hard the machine works, he says, although it requires accurate fuel records. Dale Warner, CEM, has implemented a fuel-consumption-based program at CJ Miller.
PMs for the company's over-the-road vehicles, as required by Department of Transportation regulations, are based on mileage. DOT mandates that inspections be done before the vehicle reaches 25,000 miles. Off-road equipment PMs, however, are done based on gallons of fuel used.
"Everything we do here as far as PM is concerned is by fuel consumption," Warner says. "By setting up a severity-based program, we are able to manage our PMs by workload rather than by hours. The more fuel a unit uses, the harder it is working, and that will determine the frequency of the PM."
Warner uses two preventive-maintenance categories. One is PM-A, which includes a visual walk-around. "We check to make sure everything is adjusted right," he says. "We do ongoing undercarriage inspections, tire inspections, and we take oil samples."
PM-B inspections are done when a unit is brought into the shop. "We do pressure checks and air-conditioning checks, for instance," Warner says. "If we had more time and more people, I'd probably break PM down into even more categories."
To manage such programs requires appropriate software. Although a number of different software packages exist for evaluation, Warner says the key aspect is that it includes the type of inspections you want. Most fleet-management software even has the capability to set up a PM inspection program.
"You can probably set it up within the fleet software you are already using," Dungan says.
Warner starts with information contained in manufacturer service manuals and uses that input as a base. "When the software kicks out the results, it is still itemized, but it's itemized by what we want done, such as filter replacement or whatever it might be," he says.
Scheduling is as important as the inspections. "You need specific people to do the regularly scheduled PMs, including such things as changing oil, filters, and pulling oil and coolant samples," Dungan says. And even more important, he says, is to create an environment where these things are not an option. They must be done.
"I'm a believer that the people who actually do the PMs should not be working for the guy who is responsible for break-down repairs," Dungan says. "My reasoning is that it is too easy to pull someone off an oil change to fix a broken hose and let the oil change go."
Somebody has to be responsible for ensuring the PMs are actually being done, says Dungan. "How you go about doing that isn't easy to define, but somebody has to be accountable. I'd have a separate supervisor responsible for making sure PMs are done on time and correctly."
Dungan says managers also have to ensure proper follow-up for problems uncovered during PM inspections, specifically those determined through oil analysis.
"The PM manager may receive a report on a sample taken 40 hours after a repair and the levels are normal," Dungan says. "Few managers have time to sit down and track such things as how many PPM of iron is normal for every 100 hours of operation of a machine. The reality of the matter is that the equipment manager, or the PM manager, is probably only tracking the exception reports. When a report comes back as normal, he probably doesn't even read it."
Dungan says that someone must analyze these reports, following up on them to make sure the problem was resolved.
"You might have two master mechanics on two separate jobs," he says. "The first one may have made a repair based on information from an oil-analysis report and thought he had fixed the problem. In the meantime, the equipment might be moved and the next mechanic gets the next report. Depending on how good your records are, he might not even know what the first guy did." What it all boils down to, says Dungan, is having one person to track these reports and keeping good records.
Done well, preventive-maintenance inspection programs combine manufacturer recommendation with fleet history to keep machines up and running.