The manufacturers advertise with the statement that the user of the vehicle does not have to change the oil in the hydraulic chassis once during the entire service life. "Maintenance-free" is the statement. In theory a beautiful thing, no cost. But that's only a nice thing at first glance, in practice it looks different. The cost comes with the aging of the oil. Every user should be aware that despite this statement by the vehicle manufacturer, deposits and residues will form. These can lead to considerable problems in the future, including defects in the hydraulic chassis. Problems with longer downtimes and the resulting costs can be the result. Therefore, an oil change should be carried out at regular intervals in order to maximize the life of the hydraulic components and thus also the driving pleasure. Careful maintenance of the hydraulic chassis has an absolutely positive effect on the components of the hydraulic chassis. A study that we carried out with an S 55 AMG compressor with a mileage of 470.000 km has shown that it makes sense to change the oil in the hydraulic chassis every 30.000 km in order to protect all components in the system from the liquid sandpaper. Because if there is an impurity in the system, the hydraulic oil turns into liquid sandpaper. The result is greater wear and tear, more friction (overheating of the hydraulic pump, which leads to cracking), damage to the running surfaces of the suspension struts and malfunctions of the control units. In addition, there is the abrasion of the inner walls from the hydraulic hoses, which also turns the pentosin oil black and even makes it muddy, the so-called floating particles clog the holes and microsieves in the ABC components. The tasks of a hydraulic oil include, among other things, the transmission of pressure to the individual chassis parts, absorption of forces, heat dissipation, lubrication and the operation of the hydraulic control. However, this requires a clean oil and it should not be too old. Because the prescribed hydraulic oil "Pentosin" is hygroscopic (it draws water from the humidity), the same phenomenon as changing the brake fluid every 1–2 years. The service life of the "Pentosin" oil is approx. 1,5-2 years in use. 4–5 years in normal closed storage. By absorbing moisture from the air, you have the phenomenon that your components in the hydraulic chassis rust. With longer idle times, we have already had vehicles where the pistons in the hydraulic pump were rusted and a "red error message" came up when starting for the first time in spring, hydraulic pump total loss. Then there are the broken chips, which are immediately distributed in the system, so that a complete renovation of the system is necessary. The usual problems with which a hydraulic chassis has to struggle are often caused by the use of oil that is too old. Due to wear and tear, the viscosity cannot be 100 percent retained and optimal lubrication can no longer be guaranteed. In addition, dirt particles settle over the years due to the metallic abrasion and the floating particles that detach from the inner walls of the hydraulic hoses, which continue to make good lubrication impossible. In the worst case, this can even lead to blockages of the oil strainers or the hydraulic control units, making it impossible for the components to self-lubricate. The consequence is bearing damage. Due to the insufficient lubrication, renewed abrasion can hardly be avoided. It is therefore a "vicious circle". This significantly shortens the service life of the components in the ABC / MBC hydraulic chassis. The harmful deposits caused by the abrasion can only be removed almost completely by changing the hydraulic oil, depending on the variant. A change should be made every 2–3 years, more precisely every 30 to 40.000 kilometers. In 2008 we developed the "Zädow Method" to make it possible for every user to change the oil in the system. The system's oil change is carried out by manually moving the undercarriage up and down, with new oil being filled into the reservoir and the old oil that is expelled via the return line being collected in a separate container. There are several options for flushing the system, including using a separate pump and using the Star Diagnosis. With the “Zädow method”, however, we have shown many users and workshops a method to carry out an oil change in the ABC / MBC system without costly work equipment.