Article

Has Predictive Maintenance Become a Dinosaur?

Vertical integration, underhood heat and cheaper parts have replaced experience and data bases in anticipating component failures.

March 2007, TruckingInfo.com - Feature

by Tom Berg, Senior Editor - Also by this author

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One goal of fleet managers, so the story goes, is to spec out a tractor so that it runs great during its planned lifetime, then falls apart the day after it's traded in. If you could do that, you'd get the maximum amount of work for your money. The bonus would be, your competitor couldn't use that old truck to take freight away from you.

A variation on that theme would be the ability to predict when each component on a vehicle will wear out or fail, replacing it just beforehand as part of a regularly scheduled visit to the shop.

Savvy managers always built data bases on their computers and in their heads and knew exactly when to change the various components. This is one reason they liked to spec a truck in detail, because the parts they chose were the same ones in their data bases, and they could expect the same lifetimes from each.

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Those days, alas, are gone.

Original equipment manufacturers have eliminated many options and substituted their own sets of components. This is one aspect of vertical integration, which has long been common in Europe and Asia and is now spreading among North American OEMs.

Engines and drivetrain components are the more obvious items being limited, but smaller parts are also affected. OEMs contend that their specifications are as good as what fleet managers put together because they can determine reliability through testing and infer it from the popularity of various components ordered by the majority of their customers. But managers who have lost control of componentry don't agree.

"My numbers are no good anymore," says Roy Gambrell, director of maintenance at Truck It Inc. I've got to start from scratch" in compiling a new data base with each batch of new trucks because OEMs sometimes change suppliers based on price.

"I used to know when the turn-signal flasher would wear out and could replace it. I knew within 60 days when that would happen. It might not be the flasher unit itself, but the lever wouldn't stay down to flash," a mechanical rather than electrical failure. "But now I can't get that kind of turn-signal unit anymore."

OEM specifications lists of components and parts are now much shorter. And some things a manager might spec as before – like a tilt/telescoping steering column – has itself changed, because the OEM has told its supplier to cut some cost from it, Gambrell says.

"It doesn't have grease fittings anymore and there are no nylon wear pads where it moves up and down. So before, where we could expect it to go a million, a million-point-two miles, now it wears out at 380,000.

"And when the driver grabs onto the wheel when he gets in, it begins moving sideways because it's not as strong, and an inspector sees that it moves and measures it. If it moves 3/8 of an inch or more, he puts the truck out of service."

Fleet members of the Technology & Maintenance Council of ATA fought for the so-called million-mile truck, and got it – insofar as the powertrain is concerned, Gambrell notes. Suppliers responded with long-lasting engines, transmissions and axles, but now the problem is the rest of the truck. This is what Darry Stuart, TMC's recently installed chairman, calls "cheaper trucks," and some of it is fleet managers' own fault. "We wanted low-priced trucks and lighter-weight trucks and we got them, but the quality isn't there like it used to be."

Some managers have reduced a tractor's battery complement from four to three and even two to save weight. That, he says, leads to what appear to be starter failures that are actually the result of weakened batteries sending too little voltage to the starter motors. The batteries themselves don't last as long because OEMs have beat on suppliers to lower their prices so price hikes on entire trucks could be moderated. And OEMs have used thinner metal and more composites to cut tare weight. Less heft in panels and elsewhere on the vehicle means it has "less capacity for long life," as Stuart politely puts it.

Predictive maintenance is further hindered by a recent development – high underhood heat – and by greater complexity that has come with more use of electronics, say Stuart and others. High temperatures brought on by hotter-running diesels are causing components to fail much sooner than before, and at no particular mileage levels (see HDT February). Belts, hoses, turbochargers, alternators, starters, fan clutches and idler pulleys are breaking sooner than expected, but there are seldom any patterns from which to plan.

During semi-formal discussion sessions at last month's TMC meeting in Tampa, Fla., managers complained about component failures. Examples varied. Certain fan clutches quit working anywhere between 40,000 and 240,000 miles, managers said, and underhood heat was the culprit, everyone thought. The supplier's representatives said they were aware of the problem and that engineers had made changes to try to correct it, but fleet people said those fixes hadn't worked. Chronic failures of turbos and exhaust-gas recirculation valves on certain diesels were due to their own complexity and the dirty environments in which they worked, and suppliers of those said they're working to fix them.

Sensors throughout the powertrain and chassis – prime examples of trucks' new reliance on electronics – seem to fail irregularly, as do connectors and wiring associated with them. Over the years OEMs have made improvements in electrical components, but problems haven't gone away. Stuart recommends that shops stock one of every sensor on a truck so it's ready to install should a failure occur within striking distance.

How are truck operators supposed to deal with unexpected failures, and when their data bases and experiences don't apply to new batches of trucks? As wise managers are now doing, watch what fails and when, and keep good records of everything, so another data base emerges. Talk with and listen to technicians and drivers who warn of signs of failure, and do something when trucks are in the shop instead of waiting until they break down on the road.

And inspect, say Stuart, president of DWS Fleet Services, and Jim LeClaire, another management consultant and president of T.O.P. Inc. Given the current state of affairs, inspections are more important than ever for all the items under the hood and elsewhere.

But "you can't just look at them, you have to touch, feel, turn and listen," Stuart said. "And you have to rely on a technician's judgment on changing it before the next PM."

Drivers and other employees must be enlisted in the effort, LeClaire says. "If they're not doing their pre-trips, if they're not doing it at the fuel islands and the shops, then you're missing a good tool. If they come up with a common complaint, you can investigate. Most of the fleets have a sister truck comparison, so you can go see how the others are doing. Look at leaks, belts, everything. Go all the way to the back of the trailer and to the other side of the rig, not just the driver's side. Eyes and fingers can find so much.

"It's 15 minutes to do a really good inspection and you've got to do it every day," LeClaire says. "If they're just checking off the inspection-form boxes without looking, the 10 minutes they saved is now costing you lots more" in failures and breakdowns.

How many of your drivers actually do the required walk-around inspection before they get into the truck? If they do, how many do a thorough job? And how many breakdowns and citations are you dealing with because they're not?

In fact, if you look at most fleets' SafeStat reports, you'll see that a lot of out-of -service violations are caused by things that should have been caught during the pretrip – turn and stop lamps, for instance, or tires that are flat or so worn there is fabric exposed.

Zonar Systems has a tool that could help. The Electronic Vehicle Inspection Report System uses a handheld tool to help drivers easily and accurately document their inspection observations.

Here's how the EVIR works: Durable, self-adhesive RFID (radio frequency identification) tags – fat buttons about the size of a half-dollar – are positioned around the vehicle in critical inspection zones. When a driver holds a Zonar handheld reader within 4 inches of the tag, it transmits data to the reader, such as location on the vehicle, vehicle ID and components to be inspected.

The reader then displays the list of components the driver needs to check in that "zone." If no defects are found, the driver pushes the green button and the component items are checked off. If the driver finds a problem, he or she can document the condition by pushing the red button. When the driver records a defective condition, the Zonar reader asks for more detail, including whether the vehicle would be safe to operate. It also records how much time a driver spends in each "zone."

The zones and the items included in those zones are customizable by the fleet. For instance, vocational fleets may have zones on bodies or other equipment that need to be inspected.

The reader is designed for easy, one-hand push-button operation, and even includes a built-in LED spotlight.

Once the inspection is complete, the system makes a permanent record of the inspection report, complete with an automated stamp of the date, time and VIN.

There are several ways to access the data. One is to put the reader into a mount in the vehicle. The company also offers options such as GPS systems that offer real-time data reporting, or a modem that allows for report uploads from remote locations. Zonar is working with Qualcomm to integrate the product so fleets can wirelessly transmit EVIR data using Qualcomm's mobile computing solutions.

Whichever method you choose, the inspection data is transmitted to Zonar's secure server, which can be accessed via the Internet. The system includes Ground Traffic Control, a suite of Web-based software solutions that help you manage, interpret, and report the data drivers collect during inspections.

Zonar Systems' applications can interface with your existing maintenance and routing software. Fleets save time on paperwork, and reports generated by the system make it easier to spot trends.

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