VARYING THE LOAD
Harthorn warns maintenance managers to keep in mind what kinds of environments they will put their trucks and trailers through when considering load sizes.
"If the trailer goes off road, OEMs require fleets to reduce their loads by 25 percent with pintle hook equipment," he says.
"Also when you go off road, you have a situation with articulation. The problem is rigidity. If they don't have either a swivel pintle hook or a swivel draw bar to restrict movement, the problem will be things breaking because it is able to bang around," he says.
Loading the trailer should also be taken into consideration.
"For example, how the load is distrib uted with the basic weight ahead of the trailer axles, you will end up with a huge vertical load on the coupling joint," Harthron says. This will be a problem because you can exceed the vertical capacity of the coupling joints, which can lead to a failure.
"Matching the components up, making sure the loads are equal—the tow vehicle and the towed vehicle—and also keeping an eye on how the trailer is being loaded—these are the best ways to prevent component failures," Harthorn says.
A NOSE UP
"Have you ever seen a truck pulling a load, and its front end is up in the air?" asks Monroe's Broge. "This occurs when the truck is pulling a trailer that is too heavy."
Broge mentions that there are trailers out there where people can flip the springs to raise the trailer up a few inches, but he says that scares him.
"Call me old school, but when it comes to safety, the higher the center of gravity, the more likely the truck could tip. Just because the truck may have enough power to pull the trailer, that doesn't mean it is appropriate."
Broge says a good way to lose a warranty is to tow a trailer that is too heavy. Many times, He has dealt with customers demanding warranty service on their brakes after only 17,000 miles.
"Part of warranty servicing is trying understand the problem. All we have to do is take one look at the trailers that are too big and too heavy for the trucks to find the real cause," he says.
Maintaining a warranty should be enough to motivate people to maintain their vehicles, but Broge says that's where people miss the target.
According to Harthorn, some pintle hooks require grease or light oil in the pivot points to keep them moving.
"Another situation we have is, because of the fact that these are on the back of the truck and the driver can't see what he's doing, the latches of the pintle hooks get damaged. You need to constantly check the components to make sure that the operation of the pintle hook and the latch assemblies are in good working order and haven't been damaged," he says.
"A final concern is wear. The drawbar eye and the horn of the pintle hook will wear."
Harthorn suggests that maintenance managers consult component catalogs for specific dimensions for component wear.
"Inspect the coupling contact area and periodically disassemble to inspect for wear, shank and latches, etc. Replace any component when wear exceeds an 1/8 of an inch (0.125) from the original surface profile," says Harthorn.
Harthorn recommends to check equipment more often if you are going off-road.
"There isn't really a lot you can do to prevent wear. You don't want to overload it, or exceed capacities which could not only damage the pintle hook and the trailer, but also your truck. Be sure to check the torque of the bolts that hold the components on the vehicles as well," he says.
"Just keep it well lubricated and check for wear. If the wear goes beyond what is considered safe, replace it," Harthorn suggests.
Broge says the key to a happy owner is education.
"It is my belief that the cus tomer should sit down with their dealer to discuss their needs before purchasing," he said Harthorn wants maintenance managers to reflect on the positive aspects of towing component maintenance.
"If maintained and inspected properly, towing components will usually last longer than the trailer, and with any luck," he says, "you won't ever have to replace the components throughout the life of the truck."
Keeping informed when spec'ing to cut construction fleet costs.