Turning the wheel to lock, while the engine is running, such as parallel parking, u-turns, etc. place an enormous strain on the rack. You should be able to hear the PS pump working when that happens. The owners manual even states that one should not leave the wheels in such a strained position more than 15 secs. The pump pressure gets too high and starts blowing seals.
My daughter does that when backing out of the driveway, she has it as far as it turns even when going through the gutter. I cringe when ever I hear her back out. It is seldom more than 10 secs, but when she waits for a car or truck to go by it could be 15-20 secs. Just a bad habit :)

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)