Drum leaks from the join of the drum & drum back. ( & over the motor connnector, great!). There is big circular clamp around this join, once removed, the drum back doesn't come free. How do I get this drum back off? What makes the seal? Is it a rubber seal, but there was a lot of white powder in the joint ! . How does the drum come out of the machine? out the top? ( u can't get the concrete block off because of the cross bar, held by the springs, held by the weight/size of the concrete).