MERCEDES-BENZ Vaneo Pump with ECU

Electric Hydraulic Power Steering Pump - What It Is and How to Repair It

Car manufacturers have been equipping vehicles with power steering systems for several decades. These devices help reduce steering effort and make the process more precise and predictable. The electric hydraulic pump is an important component that plays a significant role in the steering system and requires immediate repair if it fails.

How an Electric Hydraulic Pump Works

Steering mechanisms are divided into four types:

1. Without power assistance
2. Hydraulic
3. Electric
4. Electro-hydraulic

The principle of hydraulic power steering is that the pump creates pressure in the system. Using a distributor, it is directed into the hydraulic cylinder cavity corresponding to the turning direction. The hydraulic cylinder moves the steering rack rod, which turns the wheels through a system of levers. In a simple hydraulic power steering, the pump is belt-driven from the crankshaft pulley of the internal combustion engine. In an electro-hydraulic system, the pump operates from the vehicle's electrical system.

Main Advantages of Electric Hydraulic Pumps

Compared to conventional hydraulic systems, electric hydraulic power steering has several significant advantages:

• They only work during turns, saving fuel during straight-line driving
• They are controlled by an electronic unit, allowing adjustment of effort depending on the vehicle's speed
• They do not depend on the engine speed - you can steer even if the car has stalled
• Electronic diagnostics and error information for the unit are available
• Feedback makes it possible to use driver assistance systems

Despite high productivity, such a dual-action system also has certain drawbacks. In an electric hydraulic pump, the oil reservoir and electronic unit are usually located close together for compactness. Therefore, the slightest leak or breach of the seal almost automatically leads to unit failures: corrosion, short circuits, destruction of elements.

How to Identify Signs of Malfunction

The clearest symptom is a yellow or red steering wheel symbol on the dashboard. However, during operation, some signs may appear even before this. These include:

• Strange noises from the engine compartment
• Leakage of red fluid
• Misting of the power steering housing or reservoir
• Steering getting stuck during turns
• Steering jerks
• Increased effort required for turning

All of these indicate that the driver should visit a service station as soon as possible for diagnosis and repair of the steering mechanism.

Repairing Electric Hydraulic Pumps at STS.Parts

Repairing steering system components is a complex task that can only be handled by professionals with specialized equipment and experience in similar work. Our company has been solving problems with all types of power steering and other automotive units for many years. We perform comprehensive diagnostics, clean and change all necessary parts, including electronic units.

If the pump is beyond repair, we install a refurbished electric hydraulic pump from our large exchange stock. STS.Parts customers always receive repaired units that are no different from factory parts - at affordable prices and with a six-month warranty on all work and parts.