my 1994 Volvo Sedan's driver's rear wheel just totally locked up on me today. Had to tow the car. I have been hearing low-pitched sounds from the right rear for some time now and haven't been able to get it into the mechanic. The noise would be worse at times, but was most noticeable at lower speeds when I would slow down. The sound is present when I let up on the accelerator (I guess the engine noise is much less) and would slow in proportion to the wheel rotation speed of the car. It's like a scraping noise that is low-pitched. Well, the right rear wheel locked-up completely today without the brakes ever applied. OK---it's my mother-in-law's car, as I would never, ever, had allowed the noise to get to such a degree that a wheel lockup would occur...It's easier writing this piece as lst person. Could it be 1) severely worn wheel bearings 2) loose calipers 3) ABS problem 4) brake pad or brake shoe loose or brakes completely engaged due to broken brake releasing mechanism or 5) pinion disc/gear boken? Any help with this problem would be helpful so I can soothe an old woman...before she gets the word from the Swedish mechanic. Thanks.