A lot of workshops have plenty of questions about stability control systems. Some have experience with them and a lot of workshops have none, so Diesel Workshop is running a series of frequently asked questions articles. The fitment of such systems has been sporadic in the past. This situation is about to change with the mandatory fitting of some form of stability control making its way through to law. Now anyone dealing with truck and trailer maintenance has to be up to speed with just what the implications are of fitting these kinds of systems onto a vehicle.
Diesel Workshop would like to thank and acknowledge the Australian Trucking Association’s (ATA) Technical Industry Council whose Technical Advisory Procedure (TAP) is the reference on which this article was based. The aim is to provide trucking operators with key information about the fitment and operation of stability control systems for improved vehicle safety.
QUESTION: Does a roll stability unit need commissioning?
ANSWER: Yes. This has to be done by an authorised installer or system supplier. This procedure is referred to as End of Line (EoL) inspection and can only be done using special equipment by a person authorised by the brake system supplier. On completion of the EoL, the supplier should be able to issue the customer with a completion report specific to that component.
QUESTION: For a B-double combination, does the lead trailer need to be equipped with power and an ABS/EBS plug/socket to power the B trailer?
ANSWER: Yes. Each trailer and converter dolly that can tow another trailer must be equipped with a rear plug/socket in accordance with ADR38/04, to enable any following trailers to have their smart brake systems powered.
QUESTION: Does a prime mover with a roll stability function enhance the operation of a trailer roll-stability control system?
ANSWER: Yes. The prime mover with full or enhanced roll stability function has a steering wheel position sensor that indicates the driver’s intended path. It can interpret early information about the severity of a bend and the truck brake can de-power or apply the brakes to the combination as required earlier than when the trailer measures the lateral acceleration occurring.
QUESTION: I currently operate a fleet of American prime movers (12V) some with and some without ABS. What should I specify in a TEBS system?
ANSWER: The best benefits from TEBS are obtained with a full 24V system (prime mover and trailer/s). The higher potential of a 24V system allows electrical current to be carried over a longer distance. By fitting trailers with 24V TEBS systems and providing a 24V power supply (inverter) from non-ABS prime movers, and 24V signal/supply (inverted) from 12V ABS prime movers, a superior electrical performance outcome will result. There will also be further benefits when using a multi-volt trailer TEBS in long combinations. For a long vehicle, 24V systems have the advantage over 12V, provided all other variables remain the same. These variables include the quality of connections, quality of crimping at connectors, and wire size. The 12V systems are generally limited to two trailers.
QUESTION: What electrical connectors should be used between elements in a vehicle combination?
ANSWER: The ISO 1185 or SAE J560 electrical connectors (AS 4735-2003) are approved in ADR 42. These should be used for all multi-trailer combinations, and are recommended for all combinations. Wire size and quality, crimping and maintenance are important, and earth/ground wires should be given the same care and attention as power or positive wires. Trailer electrical connections have multiple power wires for different functions but only a single earth wire. A smaller diameter (cross-section) or compromised/damaged earth wire would render the complete trailer system (lighting and/or ABS/TEBS systems) non-functional.