1994 S280 Weird noise underneath!!

[Sovereign]

Please can anyone help. I bought the car last year. It is 10 years old now with a genuine 61k mileage. It has a droning noise, apparently from the rear, which is especially noticeable about 65-70mph. Sounds a bit like a loose baffle in the exhaust but I have had that replaced so it can't be that. The local Mercedes dealer cannot identify it exactly but has heard it and thinks it might be the nsr wheel bearing, but at £400 as a maybe repair seems a bit silly to me to spend the money. I think I can hear a similar droning/rattling at very low speeds, but not as loud, and especially when the car is on lock (turning).

Has anyone ever experienced anything like it?

 

[teky]

jack wheels of ground and free spin them to check for bearing noise also if play in the wheel, whilst its up off the ground check the half shafts are tightly bolted to the axel "the bolts tend to come loose", next is the prop shaft check the rubber dohnut for wear/rear of the prop going into the axel for excess play and tight bolts and lastly the universal joint for excess play