As well as premium class vehicles and sports cars, many mid-range vehicles and SUVs are also equipped with electronically adjustable dampers, such as the Sachs CDC (Continuous Damping Control). To help automotive workshops remain competitive in this expanding market, ZF Aftermarket has now greatly expanded its spare parts program for electronic dampers. With a range extension of 33 new part numbers by the end July, the business has more than doubled the number of Sachs original spare parts available to the independent aftermarket (IAM) - and the portfolio will continue to grow in the coming months.

The CDC electronic damper system has been in large-scale production since the mid-2000s and is offered for many vehicles in series right down to the compact car class. To date, ZF has produced in excess of 34 million CDC dampers. In line with this, independent vehicle dealerships can be confident that electronic dampers will be installed in the vehicles of a growing share of their customer fleets.
 

ZF Aftermarket has responded to this trend by adding 33 new part numbers by end of July to double its aftermarket offer of CDC dampers. The new to range extension covers a variety of makes and models including Audi A6, BMW 5, 6 and 7 models, and the Porsche Macan.

Reliably identify electronic dampers

But before any repair can be carried out the workshop must first deduce if electronic dampers are installed on the vehicle, so they need to know how to do this. In some cases, the vehicle owner himself or herself may not even know about this equipment feature, for example if he or she bought the car second-hand.

If the vehicle is fitted with a CDC which has an external valve, it’s easy. Here, the proportional valve, which is responsible for adjusting the damping forces, is located externally in the lower section of the damper tube.

If however, it’s fitted with dampers with internal valves, these can only be identified by the cable that protrudes from the piston rod. And this is housed in an area of the vehicle which is, in most cases, unfamiliar to the technician as they won’t visit this area even when changing the wheel, for example. Therefore, they need to look for other things which indicate the presence of an electronic damper system. These can be found in the form of switches or buttons with a damper symbol in the cockpit or display area and there will also be dashboard warning lights to show defects.

Since shock absorber wear is gradual, often drivers either don’t notice the changing driving behavior of their vehicle, or over time simply get used to it. Electronic components make it more difficult for workshop personnel to detect signs of wear on these parts, because to a certain extent the variable valves can compensate for the effects. Furthermore, electronic dampers can’t be accurately tested using conventional shock absorber test methods.

But the wear is there nonetheless. For example, if the sealing tape around the damper piston is worn away then an oil bypass will form at this point which the control system can’t compensate for. The durability of variable dampers is therefore not per se greater than that of conventional, purely hydraulic designs. At the end of the service life, therefore, the same negative effects on driving safety occur: greater body movements and loss of contact between tyre and road can lead to longer braking distances and subsequently unsafe driving behavior.

Electronic error patterns are emerging

In addition, a new class of damage is emerging, to the electrical and electronic systems. This ranges from kinked cables, corroded plugs and sensor impairment to damage caused by animals, particularly martens which are notorious for damaging the electrical systems by chewing on exposed wires and tubes beneath a car’s bonnet/hood. Thankfully, any damage of this kind is indicated by a dashboard warning light. And in some vehicles, the engine will even automatically switch to emergency mode if the damper adjustment fails.

As a true one-stop-shop, ZF Aftermarket supports its OE quality aftermarket offer with expert training. These two-day, hands-on practical training courses educate workshops on matters of troubleshooting and repairing electronic suspension systems. These courses are available for members of the ZF [pro]Tech workshop concept. The business also provides automotive workshops with an extensive range of CDC dampers under its Sachs brand. With the support of ZF Aftermarket, automotive workshops can thus benefit from the growing market share of electronic dampers and at the same time restore the familiar handling and driving safety of their customers' vehicles.