April 2020

portfolio to the independent aftermarket, along with the necessary technical information to ease installation. “TRW’s electro-hydraulic power steering system combines the advantages of electronically controlled, demand-based steering with robust hydraulic actuation. The compact motor/pump unit can be easily replaced if a fault develops; however, to avoid unnecessary returns, the motor factor should forewarn the workshop that if an early pump is to be replaced with a later version, the electrical connectors may differ. If the electrical socket on the new pump does not match the plug on the vehicle wiring loom, the wiring jumper provided by TRW with the pump must be installed.” Demanding Commenting on the re-use of nuts and bolts, Richard advised: “Vehicle manufacturers recommend that nuts and bolts loosened when installing spare parts should not be reused. A vehicle-specific Lemförder Service Pack contains new fasteners for the main component being replaced and also for peripheral components that must be disturbed, simplifying steering and chassis repairs. ZF Aftermarket currently offers over 130 service packs with OE spare parts for more than 800 vehicle models.” The government’s push towards EVs could put more emphasis on steering and suspension parts according to Richard: “Although the UK government currently plans to phase out the sale of new fossil-fuelled cars within an ambitious timeframe, this should not diminish the market for steering and chassis components. Indeed, the product quality required of suppliers may well become more demanding; quieter electric vehicles will inevitably show up non-OE mounts and bushes exhibiting poor noise insulating characteristics.” New direction The steering system has traditionally comprised of a network of intrinsic, but largely mechanical parts. However, change is catching up with steering and with new components, new materials and new service procedures evolving, it is now seeing electronics playing a more involved role in it determining its functionality. “The electronic stability programme (ESP) has brought a whole host of new electronic components, Julian Goulding, UK Marketing Manager, Delphi Technologies. “One of these is the steering angle sensor. Typically found inside the steering column, they work with the yaw, accelerometer and wheel speed sensors to monitor what the vehicle is doing, what the driver wants the vehicle to do, and what corrections need to be made by the ABS to maintain control. “While the steering angle sensor was introduced in the early 1990s, only recently has it become necessary to reset them after performing a wheel alignment or replacing a component that can alter the toe and thrust angle. Critically, the procedure to do this differs significantly between manufacturers. Some vehicles can self-calibrate by having the wheel turned from lock to lock and then centred and cycling the key, some need a quick test drive and others a diagnostic routine. Either way, steering angle reset should now be part of a garages standard wheel alignment. “Many new vehicles also feature a self-levelling headlight sensor, positioned on the control arm. When fitting a new control arm, this sensor will need to be transferred and reset, using a diagnostic tool such as Delphi Technologies DS solution, to access the headlight or body module and then perform a basic setting. This procedure will ensure that the headlights self-level to the correct position, and do not blind oncoming traffic.” New materials As with most things, there’s a trade- off and that’s the added weight of these and other electronic components. “To compensate, vehicle manufactures are increasingly using aluminium in steering and suspension parts,” pointed out Julian. “As well as reducing overall vehicle weight, helping to improve emissions and fuel economy, it also lowers unsprung weight between the tyre and spring for improved handling, and transmits 42 AFTERMARKET APRIL 2020 STEERING AND SUSPENSION Above: New MEYLE control arm for Land Rover and Range Rover models www.aftermarketonline.net Below: TRW steering racks