Victoria Car & Vehicle Maintenance - Steering - Changing Power Steering Fluid
Power steering systems, like the brake hydraulics, will wear out over time. Rubber hoses, sealing mechanisms and gaskets can break down, and the steering fluid can become contaminated. It should be changed every 40,000 miles. This is done by adding new fluid, which pushes out the old (dirty) fluid.
To flush the system, first locate the power steering pump lines. The high-pressure line moves fluid from the pump to the steering is attached with a crimped on steel sleeve. First, detach the low pressure return line, where the hose is clamped to the return nipple. While adding fresh brake fluid to the reservoir, have an assistant turn the steering wheel back and forth. Use jackstands to raise the front wheels clear of the ground. Continue to drain off the old fluid until clean oil begins to drip from the pump.
Now you can reattach the return line and top off the fluid reservoir. A few more turns of the steering wheel should be enough to force out air bubbles.
You can help extend pump and steering rack life by installing an in-line fluid filter. The filter's tiny screens remove abrasive particles that can cause pump failure. This filter is hose-clamped into the low-pressure return line to the pump. To do this you need to drain the power steering fluid, and then cut the rubber hose line about an inch or two from the return nipple. Hose-clamp the after-market filter to the free ends of the hose.