My 91 750 is in th eshop checking on the oil leak (looks like hydraulic fluid but not sure) and steering wheel vibration on acceleration on speed about 55mph. Shop is called "Eurotech" here in MN ONLY dealing with Mercedes and BMW. Mechanic said usual suspect is driveshaft and wheel balancing issue for the vibration but not in my 750. He is doing a test drive and trying to find out. I will post what else can cause this symptom. Oil leak is still under detect. Hydraulic fluid reservoir might be the cause pushing out the fluid but double check.