you are probably wasteing your time...
It can nearly be impossible to get an anode rod
out of a heater that old.......
it usually takes a heavy duty socket and a cheater bar
also its good to have someone holding the heater in
place to make sure you doesent move under the strain...
but if you are lucky and can get it out,
just the banging on that nut and effort you make
to wrench that old nut out probably will do more damage than good
to the 8 year old glass lineing
The rod helps extend the life out to a certain length, 6-10 years
depending how big a rod was installed in the unit...
after 10 years its all a guestimation how long the unit will last.
leave sleeping dogs lie.