There is little as unlovely as a failed coupling, leading to tractor and trailer parting company. Steve Banner takes advice from the industry

Taking a closer look at fifth wheels could help hauliers cut un-laden weight of their tractor units and increase the durability of a critical component. So says Andy Walton, product manager at Marcar, which distributes Italian manufacturer V Orlandi’s range of fifth wheels, drawbar couplings and trailer eyes in the UK.

“These days it is possible to do away with lead-up ramps and use the air suspension to position the truck correctly if the driver knows what he’s doing,” explains Walton. “That way you can save 50—100kg.”

Just as important, UK operators should also consider switching away from pressed steel to more durable cast fifth wheels, he says, certainly if they intend to keep the tractor for more than four years and the application is arduous. “Cast fifth wheels can last the life of the truck,” he says, although conceding that they are more expensive. “Hauliers buy on price and cast fifth wheels are more than twice the price of pressed steel.”

Nevertheless, like many others, Walton also insists that in the vast majority of cases there is little point in specifying a sliding fifth wheel. “Most operators hardly ever use them,” he contends. And Fontaine UK sales manager Steve Marshall adds that many only opt for sliders because they believe they boost residual value. “That’s a myth though,” he says.

What is not a myth is the risk of a dropped semi-trailer if tractor and trailer are not correctly coupled. That usually happens because the interlock handle has not engaged and the dog clip has not been fitted. That is why Fontaine developed Tech-Lock, which features an LED that glows green when coupling is correct – confirmed by a second green LED in the cab. “We sold over 800 Tech-Locks last year and we’ve just received an order for 350,” says Marshall says.

Similarly, Jost offers the 3 Sensor system. With a trio of sensors monitoring the lock jaw, king pin position and trailer height. If there is a problem, the driver receives an alert on an in-cab monitor.

Meanwhile, although fifth wheels are commonly associated with grease, that need not be the case. Manufacturers have been busy developing low- and zero-lubrication fifth wheels for European consumption, with SAF Holland well to the fore. Another approach is to install an automated lubrication system, such as that offered by Jost.

Drawbar couplings require lubrication too and there are divergent views on the correct approach. VBG UK sales and marketing manager Howard Ostle believes grease should be avoided because of the dirt and grit it attracts. “It can end up acting like a grinding paste,” he warns.

VBG advises the use of its own MechOil aerosol lubricant instead, or the installation of a MechMatic automatic lubrication system. That said, Marcar’s Walton is in favour of grease – so long as it is not slapped on. “All that is required is a thin film on the pin, which lubricates the bush,” he says. Both Ostle and Walton agree however that couplings should be inspected regularly.“They’re not always on the servicing schedule so they tend to get ignored,” says Walton.

Accidents can happen. “You can get large-capacity waste bins dropping onto couplings during loading or unloading,” comments Ostle. So when specifying your coupling, choose with ease of repair in mind. The guide funnel on a VBG coupling can be replaced easily, says Ostle, and Walton makes the same claim for V Orlandi products. “All you need is an 8mm Allen key and a 17mm spanner,” he says.

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