Steering Rack Boot Inspection
So you’re under the car changing the oil and you happen to look at the steering rack. Not good — it has oil drips on both boots. You check the power steering fluid and, sure enough, it’s down a little bit. So you top off the fluid and replace the rack boots, right? Nope! Wrong!
The accordion-shaped boots on each end of the rack are there to keep out rocks and dirt. They do not, however, seal the power steering fluid in the rack. The rack operates something like a hydraulic piston. When you turn the steering wheel, fluid is pushed under pressure to help you move the wheels. The rack has two high-pressure seals in it. One is set for the right side, and another is set for the left. Oil should never leak past these seals; if it does it means the seals are worn out and the rack should be rebuilt or replaced.
In many cases, the reason the seals wear is because the boots have become torn. The surfaces inside are very highly machined and do not tolerate dirt and grime well. If you see that the boots are ripped, replace them right away, as any dirt inside will shorten rack life.