While changing the hoses at our 1978 J&T 6-71N Shower Heads I see the inside surfaces are heavily corroded. I tried to see the business end with a small mechanics mirror but could not. We are not having any cooling issues at this time. Our Heads are the 90 degree bolt-on model and J&T has them (now in stainless) for $1175.00 ea. I've been searching the archives here and there's not much on Shower Heads getting replaced. We're still newbies and welcome any thoughts, thanks Craig