I posted a while back with similar hard steering in my '91 745. Suggestions ranged from changing the fluid to replacing my steering rack. I'm all for trying the easy things first, so I did a partial power steering fluid change. I simply used a turkey baster to remove all the fluid I could from the resevoir(It was Black as coal!)and then replacing it with automatic transmission fluid. I immediately noticed a big improvement in ease of steering at low speeds.

I plan to repeat this procedure now that the leftover old fluid has had time to mix into the resevoir. The proper flush is to remove the outlet hose from the power steering pump and have an accomplice turn the wheel back and forth while you keep topping up the resevoir until the fluid runs clean. I will do that when it gets warm, but here in St. Paul the high was 8 today so I'm not looking for long outdoor projects.

Try the turkley baster. It's cheap, will only take about 10 minutes, and might help a lot.

Andy
'91 745 184K, '89 244 134K, '87 245 lost the rust battle at 225K mi.