Trailers’ simplicity doesn’t excuse poor preventive maintenance

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Updated Aug 19, 2021
A tire problem can be the most common cause of disabling a trailer, so tire pressure and tread depth are critical inspection points in preventive maintenance.A tire problem can be the most common cause of disabling a trailer, so tire pressure and tread depth are critical inspection points in preventive maintenance.

Trailer maintenance often takes a backseat to servicing the tractor, with its multitude of components and moving parts. Still, a thorough on-time preventive maintenance inspection is the best way to increase uptime, decrease running costs, ensure safety and prevent violations, says Matt Krasney, vice president of fleet management for Penske Truck Leasing.

Steve Zaborowski, senior vice president for Xtra Lease, emphasizes visual inspection and the willingness to investigate potential problems.

“You should stop, take a look at it, and make sure the system is working in accordance with how it was planned to be used,” he says.

A trailer’s most neglected maintenance areas, which often are those most likely to malfunction or draw inspectors’ attention, are tires, brakes, lights, lubrication and the kingpin.

Beyond the driver’s pre- and post-trip inspections, Mark Sabol, platform product manager for East Manufacturing, suggests developing a list of weekly and monthly checks. Weekly inspections should include looking for any structural damage and verifying that all lights function, are in place and are not obscured.

“Lighting issues are easy to identify, which makes them a target for inspections and violations,” Krasney says. “Check for damaged lenses and clean, strong connections in the wiring. Loose connections, water intrusion and corrosion are all common culprits when it comes to lighting failures and can be prevented with proper maintenance.”

Krasney says water intrusion “can create significant damage over time, and significant damage can lead to structural failure.”

Sabol recommends checking the electrical system for chafed wires, missing clips and positive grounding. Next, he suggests lubricating the fifth wheel and checking for corrosion between the plate and main rail, loose or missing bolts, cracks and unusual or excessive wear before checking the kingpin for tightness.

Pay special attention to the kingpin and upper plate, says Cindy Crawford, director of maintenance and engineering for Ryder’s Fleet Management Solutions Group.

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“This carries the entire load of the trailer and can often get overlooked in a preventive maintenance inspection,” she says. “The kingpin minimum diameter can be checked with a simple go/no-go gauge. These are the only components holding the connection between the tractor and the trailer while allowing them to pivot when turning.”

Crawford says contaminants should be cleaned from the upper plate with a scraper to view the plate for damage.

Sabol says to check the landing gear mounting plates and bracing for cracks, visually inspect all air springs and airlines for chafing and check the brake valves for leaks and proper operation.

“Check for and remove any foreign material from within the dust shields,” he says. “Drain the condensation from the air reservoirs.”

The condition of trailer brakes, hoses and slack adjusters is a common point of noncompliance found in inspections.The condition of trailer brakes, hoses and slack adjusters is a common point of noncompliance found in inspections.

“Keep your top CSA (Compliance, Safety, Accountability) violations in mind as you maintain your trailer,” Crawford says. “Brakes are usually one of the top areas. Opportunities can include the anti-lock brake system. Ensure this is part of your PM check. Automatic slack adjuster brake stroke is another area to focus on. Again, this can be a top violation for trailers with CSA.”

A tire failure is the most likely cause of a disabled trailer, and Craig Porter, operations manager for McCoy NationaLease, pegs rubber as the number one trailer maintenance cost. Sabol suggests checking the tire air pressure and, if needed, inflating according to the tire manufacturer’s recommendations. Then verify that the wheel lug nuts are tight.

“Pay particular attention to tire pressure, tire tread depth and the overall condition of the tire – damage, tread separation, etc.,” Krasney says. “If the trailer has a tire inflation system, be sure that the system is activated and operating correctly, including the warning light, that all hoses and tubes are correctly installed and not leaking, and that the pressure is correctly set using a high-quality calibrated gauge.”

Brett Wilkie, Wabash National’s field service engineer for advanced design and material, says many fleets that do not use tire inflation systems have switched away from plastic valve caps. They’ve replaced them with inflate-thru metal caps, which offer labor savings.

Next, Sabol says to check the oil level in the wheel hubs to ensure proper wheel bearing lubrication, inspect seals and hubcaps for leaks, and grease all Zerk fittings.

In addition to the weekly checklist, Sabol recommends a monthly check of all welds for cracks and an inspection of the suspension system bushings for excessive wear and freedom of movement.

“Check that bolts are tight,” he says. “If bolts are below the required torque of 225 pound-feet, re-torque. If bolts are below 225 pound-feet more than once, replace bolts.”

Krasney says there are many other systems and components to inspect and maintain.

“Keep the exterior of the trailer clean, especially the undercarriage during the winter months,” he says. “Finally, don’t forget the rear impact guard (ICC bumper). It needs to be damage-free, securely attached and correctly labeled.”

Crawford says that trailers with specialized equipment have additional inspection needs.

“Flatbed trailers may have ratchet straps or a forklift mounting that need to be inspected,” she says. “We find that adding transport refrigeration, liftgates, forklifts and pintle hooks increases the need to change the PM inspection items.”

Advances in components and coating processes continue to extend trailer life and help reduce overall maintenance demands. Those advantages should be considered when spec’ing a new trailer, Zaborowski says.

“We’re trying to put features on trailers that combat some of the basic challenges out there,” he says.

Last spring, Xtra Lease migrated to air disc brakes, part of an effort to not only improve brake life and performance but also extend maintenance intervals. “Braking systems, and the things that can go wrong with braking systems, is right up there at the top of the list” of challenges, Zaborowski says. “There’s a lot less things that can go wrong with an air disc brake system than there is a drum brake system.”

Xtra Lease also specs full LED lighting and has gone to composite plate sidewall trailers to better protect against yard damage, Zaborowski says.

For many years, trailers and truck bodies have been constructed with corrosion-resistant high modulus and high-strength materials such as aluminum, stainless steel, carbon-coated steel, engineered plastics and woods, but they continue to evolve, Lee says.

“These materials are applied to specific areas such as frames, floors, roofs, doors and sills to prolong trailer life,” he says. “Today, some of these materials are being replaced by composites such as fiber-reinforced polymer resin composite and a combination of engineered metal plastic composite to improve trailer longevity.”

Wilkie says fiberglass and resin systems are proving their merit in terms of durability and repairability.

“Just as the automotive industry has adopted adhesives and bonding as one of the prominent methods of construction, the trucking industry is heading that direction in many instances,” he says. “Composite floors in dry vans have been around for nearly 25 years.”

“It’s all about extending the maintenance intervals and putting the right components in,” Zaborowski adds. “The systems that are built today are much better than they were 15 or 20 years ago.”

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