Ah, the classic split and expanded heating element on the old orange isotemp ! I've got the same unit and I think I'm on my 4th occurrence of that problem. Once I struggled to fish out broken heating elements but some stayed inside and corroded pinholes in the tank. I finally extracted them and then sealed the the pinholes with JB Weld - I'm thinking that was about 12 years ago and it's still going strong! My thermostats also failed and I got replacements for cheap - they are really a commodity item.
Amazing, but it's still going strong. Mine is 110v (on my SN) and Isotemp has long abandoned the product, but I can still google a heating element (it's 1100w versus the original 750W, but no problemo). Will be installing a new one this week, as a matter of fact. I'm now moving the preventive maintenance interval up to about 3 years - just throw out the old element even though it's working.
I'll admit this really qualifies me as a CARB (Cheap Ass Rag Bagger) but I'll be dammed if I'll pay stupid expensive for the new unit if I can nurse the old one along with minor effort every few years!