After spending a couple day at my buddies working on his teardrop trailer it was time for the two of us to devote sometime to the GMC. Sanded all the filler off the back, added some glaze where need, sprayed another coat of filler primer, and some guide coat. It was clogging the sand paper pretty quickly so we are going to let it dry a day or two and sand again. We did get the brake lines filled and bled. It is progress.