Per dealer recommendation I am trying to remove the rear brake drums on my 2007 Malibu in order to clean rear drum brakes. The drums wont budge. The parking brake is off and the wheels spin but the drums wont come off. Whats the trick? There are two rubber plugs on the front of the drum. What are they for? There is also the rubber plug on the rear of the brake backing plate which I assume is for adjusting the drum brakes. Any help in getting these drums off would be greatly appreciated. Thanks

There should be some plugs on the backing plate of the brakes. One of the plugs can be removed to access the star adjuster which allows you to pull the brake shoes in. This may help getting past the ridge that builds up on the drum. Now, the other issue may be the drum is stuck to the hub with rust. All I do is hit the area between the studs with a hammer till it all breaks loose and the drum comes off. If you have some rust penetrating spray, like PB blaster, it may help getting the drum off. I generally can get the drum off without running the star adjuster in.

The star adjuster can be turned using a small flat blade screwdriver and some tool to hold the locking tab away from the adjuster.

When I tried to remove my drums, I could never see anything when trying to find the adjuster.

My solution was to wail on the the drums with a rubber mallet (the manual said tap, which translates to thrash in my experience). You'll actually hear the tone change just before the drum breaks free. Couple more whacks and it comes off. Think I used a 2 lb mallet because I didn't have a 3 lb. But they're cheap so get a heavier one. Didn't use a mini sledge because I was afraid of cracking the drum.

Just worked on my rear brakes on a 2006 last weekend. Had similar problem with removing drum. I sprayed the center hub with some WD40 and hit the drum with a hammer. It came off. Found all kinds of dust on shoes and drum. After cleaning area with clean paint brush I found that I had at least 60% pad still left. Put the drum back on and DONE!

I've found on other cars that when you remove the rubber pad from the back of the brake assy and try to lossen the adjusting paw sometimes you move it the wrong direction, which tightens the shoes onto the drum and you have a tougher time removing the drum,IMO.
I replaced the front pads a month ago and it was a piece of cake. hope your job worked out for you...