rear wheel noise

Hi, I posted at the Skunks site about the noise coming from my rear wheel. I haven't removed the wheel yet but would like to say the noise sounds like sheet metal rubbing on metal [according to my wife, sitting in the sidecar. I am deaf].not a strong 'grinding' sound. the noise isn't steady...it goes Screee...screee.... scree... about 2 times per seconds the wheel rotates, when I was coasting down a small hill about 10 MPH..I could feel it doing that.she says it is louder when I turn right.I jacked up the rear wheel and there is no side movement at all. also no feeling of anything rubbing when I rotate the wheel . It turns freely.however, there is about 1" of free play at the tire tread, when in gear, from the spline gear. is that normal?there is no rubbing of the tire on any place at all.If you remember, a few months ago I had the rear spline gear rivets replaced [were loose] with heli coils and bolts with loctite. He said they have never failed on him all the bikes he installed.2 weeks ago I took the wheel off for a new tireI noticed the wheel was off center, and metal shavings fell out from the drum area. turns out 3 of the bolts came loose and one was so far out it was rubbing on the brake drum side on a small edge sticking out. the socket head was ground off.He replaced all the bolts again and told me to check it at 2000 miles.It has been fine since , and wheel is centered great, but now I get the noise from the wheel.the bike is a '73 R75/5 with a '77 R100RS engine. and sidecar. Bob in Sussex, Wis'73 BMW R75/5 w/'77 R100RS engineearles forks / Motorvation FII