Tips on Quieting Steering Pumps

Serpentine drive belts often require no periodic tension adjustment.

Steering pumps provide the might and muscle to "power" steering. They operate continuously, anytime the vehicle engine runs. The hydraulic steering system is pressurized whether the steering wheel is moving, or stationary. This constant displacement of fluid means a pump's exertions may produce some unsavory sounds, any time a vehicle is underway. Peace and quiet under the hood inspires confidence in a vehicle, and may be obtained by some simple inspections or minor corrections to silence steering pump operations.

Have a Belt

The belt that drives the steering pump must be kept at a prescribed tension to avoid slippage. A slipping belt can not only produce disturbing rackets at different speeds, but may also indicate intermittent loss of pump function. This is especially true at low speeds, when the load on the pump is maximized. While serpentine belts are typically kept taught automatically, V-style drive belts require periodic adjustment. Either style of belt can malfunction if the pump is not mounted securely, and squarely. Sighting down the line of belt travel might reveal a pump pulley that is off kilter. Belt tension can be checked with a specific gauge, or by examining automatic tensioner position indicators. Worn belts must be replaced to ensure proper operation.

In the Drink

Power steering fluid levels must be maintained as specified by the vehicle manufacturer, to prevent certain conditions that may irritate the ear. Buzzing and whirring sounds usually indicate fluid aeration, which occurs when the level is too low. This audible signal can change pitch as the steering wheel is turned, or show up under some certain circumstances, like climbing or descending steep inclines. Aeration can lead to foam forming in the fluid, throughout the hydraulic system, and the noise persists under all conditions. Allow time for the air to escape the fluid, before attempting to adjust the level. Adjust the level in consideration of manufacturer's recommendations, and engine compartment temperature, once the foam has cleared..

Cocktails

Dirty engine compartments can contribute to pump noise and deterioration.

Some vehicle manufacturers use a brand-specific transmission fluid for steering hydraulics, while others employ particular oils for the task. Pump seals and impellers are designed with fluid composition in mind, and adverse reactions to incorrect fluids can be vociferous and destructive. A system that requires frequent fills not only displays symptoms of leakage, but is more likely to be topped off with incorrect fluid. Inadvertently introducing fluids of different viscosity and composition to the pump reservoir can contaminate the fluid. Well-meaning, but misguided lube technicians might not notice a specific requirement for a particular vehicle, and repeated visits to quick-service oil change facilities might increase the potential for multiple fluid types being intermixed. The fluid specifications for type and level are often imprinted on the reservoir fill cap, or dipstick.

In the Doghouse

Reading the instructions on a steering pump cap or underhood sticker may be foiled by dust and road grime that has accumulated on the surfaces. Such debris can also shorten the service life of drive belts, and conceal leaks in the system. Sand and soil contacting belt and pulley surfaces can act as an abrasive, and cause premature wear. Belt tension beyond specifications, meant to silence slippage, can damage the pump, or associated belt pulleys. Consult the vehicle owner's manual, or dealership service departments to ascertain proper specifications, if the information in the engine compartment is missing, or illegible. Repair any leaks that lead to insufficient fluid supplies, and clean the engine compartment as needed, to ensure seamless and silent operation of this vital steering system component.

References

• Automotive Suspension Steering Alignment and Brakes; Walter E. Billiet and Walter Alley