Diagnostics in focus with Bowmonk
Vehicle diagnostic equipment specialist Bowmonk has explained how its product portfolio can assist in troubleshooting a variety of trailer and truck faults.
“The format of the HGV commercial trailer has changed over the years, from nothing more than a chassis connected to a set of axles through a steel sprung suspension system and the service schedule involving little more than a simple visual check of the tyres, lights and brake lining wear and chassis components,” said Bowmonk.
“These were the days when a trailer’s parking brake was activated by a fully charged air system, fed from an air tank on the trailer, which worked well until the air pressure diminished through leaking air tanks, gradually releasing the parking brake.
“This procedure was then reversed, with the brakes being applied by an internal spring mechanism, pushing the brake linings against the brake drum / disc. Now, only a constantly charged air feed working against the spring pressure will allow the parking brakes to be released.
“A significant safety improvement.”
“A modern trailer now bears a host of advanced safety features to ensure a safer driving experience is achieved. These include EBS (electronic braking system) providing a faster response to the trailer brakes when activated by the foot brake pedal, ABS (anti-lock braking system) an application to avoid a full wheel lock-up under hard braking, full air suspension affording increased stability with the airbag pressure being governed by levelling sensors which are connected to the trailer’s ECU (electronic control unit).
“Other important components are the load sensing valves which govern the amount of pressure to the trailer brakes, depending on the payload weight on the trailer. Too much air to the trailer brakes and the wheels will lock up. More importantly, too little and there is a risk the trailer will ‘jack-knife’ because the tractor unit is braking harder than the trailer.”
With all of this hardware now installed to control all of these components, the modern trailer has in effect become a vehicle in its own right, says Bowmonk – and as such commands a considerably higher level of servicing, performed by trained and qualified trailer technicians.
“No longer can we perform a service inspection of the trailer possessing a set of spanners and an intuitively diagnostic brain,” the firm continued.
“In support of this, we now use technology, in the form of comprehensive diagnostic tools like the ABS sensor tester, TrailerCheck unit and ISO Check from Bowmonk. This type of technology now enables us to connect with the relevant components on the trailer to establish the location of any faults.”
A very common defect with any modern HGV, Bowmonk points out, is a fault with either the ABS sensor or exciter ring, highlighted by a warning lamp on the dashboard.
“This is no different on a modern trailer,” said the company.
“Again, this can become a time consuming and expensive exercise, as in many cases components are replaced using the process of elimination, often when it is not necessary. Modern technology now also allows us to perform a sequential diagnostic check of these components in the form of an ABS sensor tester.
“This allows the technician to perform a diagnostic check of the sensor and exciter ring, quickly locating the fault without having to remove the road wheel – all tests completed in a matter of seconds.”
Bowmonk’s ISO Check unit checks for any breakdown in the ABS circuitry, whether it be on the truck, the connection or on the trailer itself.
“To enable these checks to function there is a need for the trailer to be powered up and in some cases a truck is not available to do this,” said the firm.
“Enter Bowmonk’s TrailerCheck power unit. This plugs directly into the front of the trailer and powers up all of the electrical circuits so that an inspection can be carried out on all of the lights and ABS activity.”
