I'm just starting the process of rebuilding an older 2550 and have already been stymied at step 2! The lower fireback will not come out! Either there is a great amount of buildup on the side walls or the back somehow is larger.....This all started when cleaning and reading forum posts and I took off the hood, which now I understand is warped and will not go back on.....I guess its a rebuild...any ideas on how to get the fireback out?