Makes good sensors
Mark Todd, general manager at Diesel Technic UK, takes a look at ABS sensors, one of the most important components in the anti-lock braking system
Arguably one of the most important developments in vehicle safety, anti-lock brakes (ABS) allow you to brake continuously without locking the wheels, and help bring the vehicle to a controlled stop.
The ABS system uses electronic sensors to detect and prevent locking of the wheels under heavy or emergency braking. In interaction with the brake system, the ABS sensors take over the brake control of the vehicle, significantly improving steerability.
How it works
On each wheel of the vehicle is an ABS sensor and a perforated or toothed disc with which the rotational speed is measured. During braking, if the sensor registers that the rotary speed drops disproportionately to that of the other wheels, it is a sign that the wheel is locking or about to lock and brake pressure on the wheel is reduced.
An ABS sensor measures the rotary speed of a perforated disc without contact by a magnetic induction. If the wheels rotate at different speeds this is evaluated in the ABS control unit. In the event of emergency braking the brake pressure on the wheel with the lower rotational speed is reduced to prevent locking.
The DT Spare Parts brand ABS sensor is characterised by its high-quality workmanship, making it built to last.
The sensor head has a corrosion-resistant, stainless-steel sleeve. It is connected to the synthetic sensor head, which has the induction coil moulded into it in a way that is both shockproof and insulating. A synthetic corrugated tube protects the sensor cable from damage.
Even the connector offers lasting protection against environmental influences, thanks to its silver-coated contacts, designed for low contact resistance. The complete set comes with assembly grease and a clamping sleeve suitable for assembly.
Hints and tips
The sensor head’s assembly supports must be cleaned before assembly of the new ABS sensor, and all rust must also be removed using sandpaper.
The clamping sleeve must be greased using the enclosed assembly grease. Only then can the sensor be pressed as far as it will go into the ABS ring using the grease.
The ease with which the sensor goes into the bearing sleeve is important, as the axial eccentricity of the ABS ring sets the necessary clearance.
The sensor cable and the corrugated tube must be assembled without tension, so that the cable ties do not damage or bend the sensor cable.
The supporting cabling must lock in place during assembly of the contact plug, so as to prevent moisture penetration.
DT Spare Parts brand offers a complete range with more than 40 000 different spare parts for trucks, trailers and buses, including all standard ABS sensors.
