I have a 68 280sl, euro delivery, 4 speed. The car was originally delivered with manual steering. I had a conversion done professionally to power steering about three years ago. I appreciate the power assist when parking and around town but have missed some precision in the steering at speed ever since the conversion was done. If I had it to do over I don't think I would. At any rate, before I put the car away for the winter I noticed that when going down the road the steering wheel wasn't centered when the car was moving in a straight line. I chalked it up to needing an alignment. Last week though when driving the car I was almost completely without any steering. Took it to a local independent who said that one of the power steering box mounting bolts had sheared off and the other had backed itself out to the point of almost letting go. It's repaired now, and I am writing to ask if others have experienced the same and should periodic checking of the security of the mounting bolts be considered routine maintenance? Thanks.