Brake Drum Cover

I am trying to change my rear brakes and one of the covers is stuck..Any tricks I can try to get it loose?

Do you mean trouble removing one of the brake drums? Do you have rear discs and a drum for the e-brake or just drums? I don't understand "cover". You should add your vehicle year/engine/miles to your signature.  

I guess its the drum itself
 
1991 2.0L Camry 158,000 miles

It's probably rusted to the hub. If you can see the hub axle coming through the center of the drum then spray a little penetrating fluid there. I would look for two threaded holes in the drum close the center. They are probably 6 or 8 mm. They are meant to help remove the drum but you need to be careful you don't tighten too much while the drum is still seized to the hub. They are only meant to aid removal, not force it. Get two bolts that will thread into these holes and turn the bolts against the hub while hitting the drum with a hammer and using penetrating fluid. It should ease out. You also need to make sure the e-brake is backed off and/or the shoes if this is drum only and not disc brakes (you didn't say). Of course if it has a one piece rotor and drum you will need to remove the caliper first. If you need more help you should post a pic.  

Thanks Pedro..As usual your advice was right on..The threaded holes did the trick!

when removing the brake drum cover is it ok if im on PARK or i have to shift to N?

It's not a brake drum cover, it's a brake drum, unless you mean the backing plate. You didn't give year so I assume you have discs front and rear with PBrake drum or only drum rears. If that is the case it doesn't matter if in P or N as you are FWD. If you have drums in front then use N but chock the rear wheels for safety. I just inspected my rear brakes this weekend. The PBrake is difficult to get to behind the hub. I left my hub in place and did not remove the parking brake shoes. I only washed down and lubricated as well as cleaning and greasing the caliper and slides. I found I need a piston boot for PS. If I were to replace shoes I would remove the hub for access but you may need a new bearing grease o-ring for reassembly. You could do a bearing re-grease as well while you're in there, which is what I am planning to do the next time as the shoes are pretty worn. It appears removal of the bearing needs a press, but I think re-grease is possible with bearing in hub.