Seem to have slight play in steering, approx 1" of steering wheel movement at center. Shop says they have taken as much play out as external adjustment will allow. What else could be cause or is this normal for this model. Have 70,000 miles and new BS Potenza RE 730 tires.

I had this problem with my 1996 SL320. The wheel felt loose a little each way off center, and turning it further would "trip" into providing steering input, so to speak. It was as if there was a notch that had to be overcome about 1/2 inch each side of center. The steering gear was replaced under warranty. This was an expensive part retailing for about $3,200 if I recall, so I hope your problem is something less expensive

I had a simular problem with my 78 sl. It turned out to be a knuckle that goes from the steering shaft into the steering box. I bought a used one for 11 dollars and had it installed for 50 dollars. Larry