Defective servo pump - is it worth repairing?

The power steering pump is also known as the power steering pump and is an important part of the hydraulic power steering system. Your job is to to support steering power, thereby reducing the steering operation force. There are two types of power steering pumps: the mechanical, which is operated by means of V-ribbed belts, and the electro-hydraulic. Because modern vehicles often come with an electromechanical steering gear without servo oil are equipped, servo pumps are no longer required for this. However, wear contributes to the fact that the servo pump no longer functions optimally after a few years. Typical wearing parts are the seals on the pump cover, on the hose line connections and on the suction port.

Function of the servo pump

According to road traffic regulations . the steering mechanism of the vehicle ensure easy and safe steering. The power steering supports the driver in steering his car without much effort to carry out, mainly when maneuvering. A distinction is made between three variants:

• Hydraulic power steering
• Electro-hydraulic power steering
• Electrical power steering

The hydraulische Power steering is the most common variant. The steering process in the steering gear is supported by varying the system pressure. The pressure forces are transmitted by means of hydraulic fluid, the servo oil. electro-hydraulic Power steering is based on the same system. The difference to hydraulic power steering is that a Controller is used, which is equipped with a converter that adapts the pressure to the driving speed. A more direct steering at high speed can thus be realized. In the electric power steering, also known by the abbreviation EPS, the force of the servo motor acts directly on the steering, so that no hydraulic fluid is needed. These systems have the advantage that they can be combined with different driver assistance systems and thus increase driving comfort. In addition, by eliminating the servo oil, they have one lower fuel consumption and are thereby more environmentally friendly.

How do I recognize a defective power steering pump?

The following symptoms are moglicherweise about a defective or leaking power steering pump:

• Stiff steering / only with increased effort
• Oil is leaking around the power steering pump
• Lines and shaft sealing rings are leaking
• Grinding noises when steering
• Squeak when steering
• Grinding noises when steering
• Too little servo oil, which leads to a defect in the servo pump
• Foaming in the hydraulic fluid reservoir
• Entry in the error memory, for example "power steering pump short circuit"

Can the symptoms also have other causes?

In the case of mechanically driven servo pumps, problems with the V-ribbed belts Can be a trigger for limited power steering, for example if the V-ribbed belt not properly tensioned or torn is. A defective steering gear can also cause some of the symptoms mentioned above. It is therefore advisable to have the causes clarified by a specialist workshop. The error is quickly found by checking the servo pump pressure and the flow rate.

Is a defective power steering pump reported during the general inspection?

Only occurs during the test drive Grinding noise on, this is only considered a minor defect (GM) and this is noted in the test report. However, if the servo pump no longer works or is leaking, this is rated as a major defect (EM), which means that the main inspection has not been passed.

Do I have to go to the workshop with a defective power steering pump?

In vehicles with an electro-hydraulic servo pump, in particular, a defective power steering pump is a serious problem security risk, because these vehicles are then difficult to steer. In addition, there is a risk that the steering gear will also be damaged and this will result in high additional costs if you simply continue driving with the broken servo pump. You should therefore visit a workshop as soon as you notice changes in steering behavior or unusual grinding noises.

Repair or exchange?

That depends on the cause of the defect. A broken bearing or seal can be exchanged separately. With an electro-hydraulic servo pump, however, the cause is often a defect in the control unit. But even that can usually be repaired without any problems. Otherwise, however, a complete replacement of the servo pump is necessary. With a mechanical pump, however, it does not necessarily have to be a brand new component. Used parts with a low current value of the vehicle also do a good job. And one too refurbished pump is a cheap alternative to the new part.

workflow

Exactly how the replacement is carried out varies from vehicle to vehicle. Generally, first the Engine cover removed. Then you usually have to right front wheel and the Wheelhouse Lining be dismantled. In the case of a hydraulic servo pump unit, the V-ribbed belts be removed. After that the hydraulic fluid drained and disposed of in an environmentally friendly manner. Then the pump is changed and the dismantled components are gradually reattached in reverse order. Finally, new servo oil is poured in and the system is bled. Then the test drive can take place. If the pump is in a difficult-to-reach location, however, the effort is often greater. For example, there is a possibility that the bumper and the cooler behind must also be dismantled.

How much does it cost to change the power steering pump?

The material costs depend on the type of pump, vehicle and spare parts manufacturer. The price for a hydraulic servo pump driven via the V-ribbed belt is between 100 and 600 Euro. Electrohydraulic power steering pumps are much more expensive and cost between 300 and 1.500 Euro. However, the problem often lies with the control unit, which can be repaired in a specialist workshop. The new servo oil costs between 10 and 20 Euro. If the servo pump is driven by a V-ribbed belt, this must also be replaced. The costs for this are between 10 and 60 Euro. The working time for the change is usually three hours. The exact time required depends on how many components have to be dismantled and reinstalled later. If the hourly rate is 100 euros, the labor costs amount to 100 to 300 Euro. With mechanically operated pumps you have to decide between 200 and 900 Euro calculate, with electro-hydraulic servo pumps the total costs are up to 1.900 Euro

The following note is essential: For safety reasons, tuningblog recommends all repair, inspection and maintenance work exclusively to be carried out in a specialist workshop! Although our information is summarized to the best of our knowledge and belief, we cannot assume any liability for the content. All information is therefore "without guarantee".