Do I Need a Power Steering Flush?

The easy answer is if your vehicle’s owner’s manual says you need a power steering flush at a regular interval, then yes, you need a power steering flush at those particular mileages. Since most of us don’t regularly look in our vehicle’s user’s manual it seems more likely that your mechanic, or the guys at the local quick lube shop said your vehicle could use a power steering flush. Today we will talk about why it’s necessary to flush a power steering system, how mechanics determine its time for a flush and the processs of how to flush power steering fluid.

The power steering system in your vehicle is there to aid you in turning the wheels at low speeds. Today’s vehicles are equipped with larger heavier and wider tires and wheels than older vehicles. These tires are designed to grab the road to make sure you do not lose traction in a corner or during acceleration. Without power steering, these road grabbing tires would be extremely difficult to turn without a school bus sized steering wheel, or the help of your power steering system.

The power steering system consists of a pump usually run by a pulley and belt to the crank pulley on your motor. This pump pressurizes the power steering fluid which is then carried by a line to a power steering gear box, or a rack and pinion. The steering gear, or rack and pinion, uses this high pressure fluid to help with the motion created by you turning the steering wheel, making it much easier to turn the wheels. Once this high pressure power steering fluid has done its work to turn the wheels, it returns through a line to the power steering fluid reservoir near the pump. Since there is very little motion or friction in the power steering system, the working fluid stays relatively clean and free of wear products. Unlike your engine and transmission, there is so little wear in the system there is no filter to help keep the power steering fluid clean.

Over miles and time, small amounts of wear products will build up in your power steering fluid. These wear products are bits of plastic, rubber and metal from inside the system that naturally wear off over time. As these particles are pushed around in the power steering fluid, they can accelerate wear to many of the seals on components in the system. Since there is no filter in your power steering system, the only way to remove these small particles is to remove the power steering fluid and add new, clean fluid. This is called flushing the power steering system.

A good mechanic will recommend a power steering flush at the factory recommended intervals, or when the power steering fluid becomes dark brown or black. Unless your vehicle gets heavy use like hauling, towing, or extensive idling, the factory recommended interval is usually a very safe interval.

There are two ways you can flush your power steering system:

There first method is to drain and refill the system. Start by removing the lowest power steering line you can find, often at the steering gear, rack or cooling lines. Allow the system to drain completely, which may be a while due to the viscosity of power steering fluid. Once the system is drained, refill the power steering reservoir to ½ full. As a friend starts the vehicle, add fluid to the reservoir to try and keep it half full. You may experience foaming or bubbling as the air pockets in the system are pumped to the reservoir. Once a steady level is reached, top off the reservoir and replace the cap.

The second way is more difficult but exchanges more fluid and performs a true flush. Find where the return line leaves the power steering gear or rack to return fluid to the power steering reservoir. Remove it at the low point in the system. Have a friend start the vehicle while you add power steering fluid to the reservoir to keep it at least ½ full and another friend watches the now open return line. Power steering fluid should flow from that open port into your drain pan as the vehicle runs. Once the fluid running out is clean and obviously new fluid, shut off the vehicle and replace the power steering return line. Restart the vehicle to remove any air trapped in the system with the cap to the power steering reservoir removed. Once no more bubbles or foam are in the reservoir shut off the vehicle, top off the power steering reservoir and replace the cap. Before attempting this procedure, ensure you have plenty of power steering fluid and qualified friends.

IMPORTANT: Any time you are adding power steering fluid to your vehicle, make sure you use the factory recommended fluid. Many cars take power steering fluid, but many use automatic transmission fluid or a variety of other working fluids that cannot be mixed.

Anytime you are doing a power steering flush, it is a good time to inspect the seals and hoses in your power steering system for leaks. As a power steering system ages it is possible for the hoses to begin to slowly leak, or seals to wear down, dry or crack. If any leaks or discovered, even a slow weep or potential leaks, add BlueDevil Power Steering Stop Leak to the new power steering fluid you add. BlueDevil Power Steering Stop Leak is a power leak stopping agent that contains no particulate matter to clog, damage, or wear down your power steering system. It also is not a petroleum distillate so it will not destroy the seals or hoses if it’s left in your system. BlueDevil Power Steering Stop Leak is guaranteed to permanently seal your power steering leaks and can stay in your power steering system preventing future leaks.