Signs of a defective hydraulic power steering pump

Although electric power steering is becoming more and more popular today,  hydraulic power steering is still firmly established and in demand.

One of the main elements of power steering is the pump, which creates and maintains the necessary pressure in the system and ensures oil circulation.

The power steering pumps are either vane (vane) or gear pumps. Vane pumps are the most common - they are very resistant to wear and have high efficiency. In comparison, gear pumps are even simpler and more durable, but less popular.

Signs of a malfunctioning hydraulic steering pump

Despite their longevity, hydraulic fluid pumps do break down. Failures are accompanied by the following signs:  

Signs of a faulty hydraulic pump

Despite their longevity, hydraulic pumps do break down.

• the steering wheel becomes “tight” (it is difficult to turn) after some time after the beginning of driving. It is also difficult to turn the steering wheel at high ambient temperature;
• there is a vibration in the steering wheel when turning to one side;
• pump hum in the extreme position of the steering wheel or periodically appearing hum, squeal;
• the working fluid in the reservoir foams and/or becomes dark;
• appears uncharacteristic for GUR fluid burning odour;
• oil stains under the engine after parking;
• the belt whistles of the hydraulic fluid pump.

How long is the service life of the pump. Troubleshooting

The life expectancy of a power steering pump exceeds 200,000 kilometres. Some experts claim that pumps last almost forever if properly maintained.

Want your pump to last as long as possible? Follow these tips:  

How to keep your pump running as long as possible?

• Do not use dirty or old oil. Routinely change the oil in the system every 45-60,000 kilometres or every 2 years, depending on your driving style and operating conditions.
• Care for the seals - over time they lose their properties. If you bought a car not from the salon and poured new oil, pay attention to whether it does not leave the tank. If the amount of oil decreases suspiciously fast, there is a leak somewhere.
• When choosing oil for replacement, do not chase the lowest price.
• No need to pour additives and other «repair» fluids, if there are signs of malfunctions.
• Check the tension and condition of the belt of the turbocharger pump.
• Monitor the tension and condition of the turbocharger pump belt.
• Do not hold the steering wheel in the extreme positions before driving and for longer than 5 seconds.

GPSD Pump Diagnostic Equipment

It is often impossible to visually assess the technical condition of most parts of the car. Only the results of diagnostics on specialised equipment will show whether the pump can be repaired or needs to be replaced.

Diagnostic equipment for hydraulic pumps

For example, the MS604 bench can diagnose single and dual circuit mechanically driven hydraulic steering pumps. With the help of the stand you can determine whether the pump creates pressure and what kind of pressure, measure the flow of working fluid at different speeds, check the operation of the pressure reducing valve. The testerMS611 can determine the technical condition of the elements of the hydraulic power steering system directly on the car - the master determines whether it is necessary to remove the pump for further repair.