In this article, we explore two different problem areas within your brake system, including your ABS system. We provide you with possible causes as well as suggestions to repair them.
The Problem: The Latest Brake Legislations
Here are four possible causes and suggestions:
- All new trailers above 3,500 kg GVM, built after 14th February 2004 in South Africa must be fitted with an ABS brake system that has been internationally approved. These new trailers brake systems must meet the braking requirements as described in the SABS ECE R13 brake specifications. These systems must also be kept in good working order at all times in order to pass COF tests.
- In addition, these new trailers must also be fitted with Automatic Slack Adjusters. Good quality Automatic Slack Adjusters are essential for continuous and proper operation.
- It is not a law in South Africa that trucks must be fitted with an ABS brakes system, however, most imported trucks come standard with either an ABS or an EBS brake system.
- A few other requirements that are listed in the SABS ECE R13 brake specifications are as follows:
- According to SANS 20013 specifications, the flexible Suzy hoses must be part of the towing vehicle when towing a semi-trailer. According to this specification, the couplings are fitted on the Truck Tractor at the end of the fixed Suzie's and the couplings must be fitted with automatic shut-off valves.
- The Emergency line on the semi-trailer is fitted with a fixed Male coupling and the Service line is fitted with a fixed Female coupling and a valve lifter, (striker plug).
- The suzy hoses do not have to be coloured 'Red' and 'Yellow', as long as the Service and Emergency tags are coloured correctly.
The Problem: Trailer ABS System
Here are four possible causes:
- The 'Green' marker light is wired to the trailer's ABS system to indicate to the driver if the ABS system is functioning correctly. With the truck stationary and the brake pedal applied, the green light should come on for 2 seconds and then go out. If this happens it is an indication that the ABS system is functioning with no electrical faults. Any other sequence, (i.e. light stays on or light does not come on at all), indicates a wiring fault or internal failure of the ABS electrical components. The green light is electrically connected to the trailers 'stop light' wiring system.
- EBS and ABS systems that are connected using permanent power cables, (this is compulsory if the towing vehicle is fitted with ABS or EBS systems), use the trucks dashboard indicator lights to check on the functioning of the truck and trailer's electrical brake systems. If permanent powered cables are used it is not necessary to fit a green light on the trailer. If it is fitted will only be there as a back-up system. Trailers fitted with green marker lights were originally fitted to trailers fitted with ABS brake systems that were towed by a truck that was not fitted with an ABS or EBS brakes system.
- "WARNING!!!” never weld on the chassis of a vehicle that is fitted with an ABS or EBS brake system, or any other electrically controlled, system, without first disconnecting the main electrical feed cable to the ECU and all the sensor cables. Failing to do this can seriously damage the 'Mother Board' in the ECU, which is a costly unit to replace.
- Other than a damaged ECU, the other common reasons for an ABS system to malfunction are due to one or more of the sensor cables being broken or faulty, or the gap between the sensor and the pole wheel, (exciter ring), being too great. If it is a gap problem, then by pushing the sensor in against the pole wheel should solve the problem. The sensor and pole wheel gap will automatically reset itself when the vehicle is back in motion. The sensor will not be damaged if it makes contact with the pole wheel as it is made of very hard material.
These are another collection of handy tips to repair your air brake system. If you need professional help, JMR specialises in brake systems and parts and we uphold the highest standards in workmanship. Please contact us today for all your brake system needs.