DaveRave

Just a final note. When using the two threaded holes with bolts that fit, you may actually experience two pops. If the drum is still stuck after the first crank the other bolt in farther. This has happened to me. Usually though the rust bond in total will be liberated with the first audible POP especially if you cranked the two bolts in at about the same depth. Then the drum should move back and forth yet still be tight. Drums not only wear with rear shoe friction (braking hydraulic pressure) but any untreated drum area will rust in place with moisture humidity and air (oxygen). If the drums have never been removed and the vehicle has 90,000 miles then expect the outside to be oxidized and a ridge will form on the inside of the drum near the outer edge where the shoes do not contact the drum. And it's that rusty crusty ridge that will be the last impediment to drum removal. Pop off the rubber adjuster window plug and back off the star wheel. From the backing plate top side my Helms manual says pry it up with a screw driver while pushing or holding the adjuster lock arm out of the way.

Final caveat - this should pop (audible sound) the rust bond between the hub and drum. You can certainly help it along by applying penetrating oil or pounding on the drums between the studs. However if your drums are grooved you may still have to loosen the adjuster(s) to remove the drum(s). I would caution against using too much heat since the brake cylinders do have rubber boots around the pistons and the drums may be brittle or worn so go easy with the pounding also. If you are replacing the drums then by all means have your way with them.

Size of the holes on my rear brake drums (2006 Silverado LS1500 V6 Std cab long bed 2WD 5spd) is 10 mm 1.5 thread and 25mm in length. You can probably get away with shorter ones like 20 mm. Took me two trips to HomeDepot to find this out since I misplaced ones I used previously. Mine will be free once again.