The problem on Bendix model EC-17-1030R ABS units occurs only at speeds of less than 20 mph. It happens when either a frayed wire leading from the ECU to the wheel-end or a worn or bent tone ring sends erratic signals to the ECU. Although the ECU should be able to decipher the erratic signal, for some reason at low speeds it is not able to. The result is a several-second loss of braking power while the ECU figures out it's having problems and shuts down, leaving the driver with regular, non-ABS braking.
Bendix first became aware of a potential problem with the report of a bus incident in March. The company began looking for a cause, and on July 17 notified the National Highway Traffic Safety Administration of a problem with the worn wires. As a result, International Truck and Engine Corp., which makes the Bendix ABS standard on its trucks, issued a recall of more than 104,000 trucks built between March 1998 and May of this year, including Model 2000, 3000, 4000 and 9000 trucks.
"We investigated further and found out that the ECU should be able to decipher the erratic signal that's caused by that wire chafing," says Bendix spokesman Rick Batyko, "so on Aug. 22 we informed NHTSA that we're recommending the OEs recall all the trucks so we can replace this unit."
While International has the most vehicles affected, the Bendix ABS also is found on Freightliner, Volvo, Mack, GM, Ford heavy trucks, and Magnum yard tractors, along with several other manufacturers of buses and other equipment. DaimlerChrysler yesterday launched a recall of about 40,000 Freightliner trucks and about 6,000 buses from its Thomas Built Buses subsidiary.
There have been 40 incidents involving buses and trucks, Batyko says. Only one of the truck incidents involved a tractor, he said, and the defect does not affect the trailer braking. There have been no accidents with buses; there have been five minor accidents involving trucks.
Truck drivers should keep in mind that if they're bearing down hard on the brake pedal in a panic situation when this happens, that when the regular brakes kick back in, they'll be in a virtual panic-stop situation, leading to possible loss of control and being thrown forward in the cab. Batyko stresses that the emergency brake is still available when the braking power is lost and can be applied to avert an accident.
Bendix is beginning its replacement program with school buses, followed by the rest of the bus population, then on trucks and other vehicles, focusing attention on the ones with the most incidents reported. The company anticipates the whole process will take until April of next year, Batyko says. They have upped the production of replacement kits from 9,000 a month to 39,000 a month and are getting them out into the pipeline as fast as they can, both to OE customers and through Bendix's own distribution network.