Troubleshooting ABS on the cheap

by John Curran

DON MILLS, Ont. – To a mechanic working 20 years ago, terms like blink codes, PLC for trucks and exciter rings would sound pretty far removed from their job.

Nowadays, however, these are all part of the new speak that has grown out of the mandating of anti-lock braking systems on North American commercial vehicles. Unfortunately, fixing these systems has proven a little trickier at times than coming up with new words and phases.

“More time is wasted by technicians diagnosing problems with ABS than fixing them,” Ian Sturrock, of QuikX Transportation, complained while moderating a recent panel session at the 39th annual Canadian Fleet Maintenance Seminar.

They don’t need to be insist Canada’s foremost ABS experts. There are just a few keys to minimizing costs and headaches while maximizing uptime.

“It starts with installation,” he contends. “If it’s not installed properly, your system (will be trouble).”

Even when systems are correctly engineered onto a rig, problems can surface. Waszkowski adds it is important to catch all of the bugs in a system the first time through the shop or a fleet’s costs will only increase.

“Technicians like to wave that magnet (to reset the in-cab fault indicator) and send the truck right back out on the road,” he complains. “If they haven’t done a proper job troubleshooting, that vehicle is going to be right back in the shop.”

Chitta Bera, technical guru with Haldex Canada, says if you’re going to check everything a great place to start is with the wheel speed sensors.

“Sensor gap is the most common problem,” he explains. The issue, as he sees it, revolves around the fact these critical – yet very sensitive – pieces of equipment are held in proper alignment by small less-than-rigid clips. If a clip bends, you’ll end up with an ABS fault.

Another low cost piece of standard shop fair is also at the root of many problems. The little tie-ups used to hold wiring in place have led to more ABS faults than he cares to estimate. When a technician reefs a tie-up too tight it can slice through the protective coating on the outside of the wires. Throw a little salt and road grime into the mix and it’s a recipe for corrosion.

Wiring – especially that in the neighborhood of a truck’s air valves – can also be problematic in the diagnosis phase of repairs.

“A problem can either be in the valve itself or it can be in the wiring harness,” says Richard Youngblood, of Eaton’s Truck Components Division.

“Some mechanics will simply cut a valve out that’s fine and meanwhile that unit will still have the same problem.”

Mark Melletat, of Arvin Meritor, stresses it is important not to overlook the lifeblood of your ABS system when troubleshooting problems. “When it comes to your air, the cleaner it is the better,” he says.

Some fleets have even made the switch to screened glad-hands after finding insects migrating across the continent snugly encased in one of their truck’s air lines.

As well, Bera stresses technicians should never see anti-lock systems as the panacea of braking.

“You still need to regularly check the condition of your foundation brakes,” he concludes.


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