1991 Mercedes-Benz 420SEL Power Steering System Leak Inspection Cost

For most vehicles, the power steering system will last well over 100,000 miles before any failures occur. Mechanical failures and leaks in the power steering system are considered usually avoidable if maintenance has been performed according to the manufacturer service intervals. Keeping the power steering fluid fresh, and the system free of contaminants is the key to ensuring long power steering system life. As any system that carries high pressure will, the system will eventually fail from normal wear and tear, but this should be well into the serviceable life of the vehicle.

Since most power steering issues will generate the same symptoms, it would be difficult to diagnose only one part, without understanding the condition of the whole system. When symptoms emerge, the power steering fluid is inspected, and topped off, and the condition, and tension of the power steering pump belt is noted. The system may need to be bled of air prior to diagnosis. Any leaks will become very obvious at that time, and mechanical failure of the power steering pump will be evident from noise, or a pressure gauge inserted into the power steering line. At that time, if no other issues are found, the steering rack or steering gearbox will be suspected of failure. Any dust boots and seals will be inspected for leaks. The rack and pinion gear set will be inspected for sounds typical of mechanical failure. This systematic approach will lead a technician to a diagnosis.

Power steering leaks are corrected by replacing or rebuilding the leaking component. In some more fortunate circumstances, the power steering lines may simply become loose, and will be properly tightened to prevent leaking. In most other situations, the power steering fluid is drained, the defective component is removed, and a rebuilt or new component is installed. Once the system is reassembled, the power steering system is filled with power steering fluid, according to manufacturer specification. Finally, the system is bled of air, and the vehicle will be tested for leaks and other symptoms.

We recommend against any product that claims to stop leaks in the power steering system. These products contain sealants that will become contaminants as they cure in the power steering fluid and build up inside components that are only designed for power steering fluid. This can lead to failing power steering pumps and steering gears, and even cause additional leaks.

Power steering components are subject to high pressure, high heat, and high speeds. Selecting parts that are built to meet or exceed OEM standards will help ensure the longevity of the power steering hydraulic system. Inferior parts tend to lead to repeated replacement.

Finding and diagnosing a power steering leak can be very easy, or very frustrating. The advanced DIY can generally find the leaking component, but for the most part, the issue will be a mystery. The engine fans can blow power steering around when it leaks, and a leaking pump may cover the reservoir, and lead to an incorrect diagnosis. In some instances, even professional technicians need to use an oil dye to detect the source of a leak. If the leak is not obvious, and the next step is changing parts, consider trusting a professional instead.