To remove dents from the grain unloader tube; Find an old flat belt pulley, just a little smaller than the tube. Fasten a piece of pipe or shaft thru the centre and push it down the tube, tapping out the dents as you go. On large dents; acquire a small heavy duty screw type jack that will go into the tube with lots of clearance. Find 2 pieces of say, 1_4"x 4" flat metal, rolled to about the same circumference as the tube and each one covering about a quarter of the tube circumference. Weld one to the top and another to the base of the jack. Firmly attach a long shaft to the jack winder. Slide the compressed jack into tube to the dent. Wind out the jack against the dent while tapping with a hammer. It works! I hope this helps.