Monday, February 19, 2007
Power Steering System Update
I experienced an unintended consequence of the power steering system work. When I took the car out for the test drive on Saturday the steering felt fine, but that test drive only took about 5 minutes. Yesterday I took the car out to lunch and drove it for about 40 minutes. Near the end of that driving session I felt the steering become tight and with intermittent power assist. The more rapidly I tried to turn the wheel, the more the system fought me.
I initially thought it was a simple matter of bleeding the system because I'd just ridden over some rough pavement and figured I'd inadvertantly freed some trapped air that was causing the pump to cavitate. I also considered the possibility that my power steering system was behaving like so many old BMW transmissions do after fluid changes and the rack or the pump was slowly failing.
To get to the bottom of the problem I did the only thing I knew I could do...bleed the system again. I put the car back up on the stands and cycled the wheel lock to lock another 10 times. The fluid in the reservoir dropped a bit and I found many small bubbles in the top of the fluid which indicated that I did manage to free some air. The following test drive provided less than promising results. The symtoms were initially improved, but when it came time to take the last turn into my driveway at low speed and low engine rpm I turned the wheel rapidly it felt like I had no power assist whatsoever.
This morning I resolved to take the car to my tech to discuss the problem and have him fix whatever needed fixing as I couldn't risk driving the car with problematic steering. When I described the symptoms, his long experience suggested that it was a simple matter of the belt slipping because I accidentally contaminated it with ATF. He said it only takes a drop or two on the pulley to spread to the entire belt over time and a good shot of brake cleaner should take care of it. The dealer's parts department stocked BrakeKleen so I bought a can and watched as my tech hit both the power steering and water pump pulleys with the cleaner while the engine was off. He then asked me to start the engine while he sprayed a steady stream at the power steering pulley and belt to help dissolve the ATF. After 30 seconds, I was able to turn the steering wheel with one hand again and knew I'd just dodged another bullet.
So, the moral of the story is to keep ATF off the belts and have a full can of brake cleaner handy in case you mess up.
Mileage: 139285, Parts $5