I've got a 1991 626 GLX but i am having trouble removing the rear brake drums so I can change the brake shoes.Do I have to unscrew the hub nuts?IF so how do I as they are on tight.

I have an 88 mazda 626 - WHICH IS SUPPOSE TO BE THE SAME MODEL. The drum should just slide off over the rear hub studs. If it does not, it may because the drum is so worn that there is a lip in the drum, and the self adjuster on the brake shoes are keeping the shoe in such tight position in the drum, you cannot slide it off with the shoe sitting "inside" the lip. You could loosen the self adjuster and see if that helps. Also the drum may be a bit rusted to the hub flange. Bang (not too hard) a hammer on the face of the drum between the studs in a couple of spots and see if it comes loose. Good luck with it.