Combines Knock in Drum on 7720

[tj]

It sounds as if you've broken the weld at the center hub of one of the cylinder spiders. This can slip sideways and if one of the cylinder bars is bent a little bit, the opposing (usually) cylinder bar can contact the rear beater. It's also posible that if the machine slugged hard enough that you've put a twist in the cylinder bars, since all but 2 of the 6 spiders are floating on the shaft.

 

[sri]

does this happen with the header off,or on.could be a broken weld on spider,bent rasp bar or bearing out,bent beater bar.lot of things can cause it. If it only does it with header on make sure elevator chain didn't jump a tooth on the sprocket. Post back with the problem when you narrow it down.Please

 

[Down_under_7720]

Found the problem. The spacer disc between the shaft and the barrell of the beater has a fracture in it at the right hand end of the beater. The pressure of the plug forced the barrell out of plumb. It means a new beater ! Thanks guys!