Brake Noise

OKAY!!! my damn brakes are becoming an embarrassing problem. the rear (95% sure its the rear) brakes are squeaking/grinding sounds,mostly a deep squaek that almost makes one think its metal to metal grinding.I know its the rear cause i tested the noise by pulling up the e-brake slowly and it did it.NOW, me and my father have taken them apart....rotors are in good shape,over half a pad left on both sides and the pads arent glazed over or excessively slick.So,the only my dad could think was it has something to do with the adjuster...so we wd-40'd the hell out of it,and it stopped squealing for maybe 20 miles,now its back.I dont know what to do,everything appears to be in order.It is such a bad screeeeeeech that one would think the pads were bad,but al looks dandy.Any Suggestions??????

Maybe the caliper? I'm just guessing.

Maybe the caliper? I'm just guessing.
i really dont know. It looks fine. like the first 10 or so stops i make after first getting down the road it doesnt do it...but then it starts to do it constantly.And after cruising round town a while...every stop makes this squeaky grind noise.
AnyOne Help???
thanks for the reply bud