Bronze Stem Head Fitting Inspection

[Brion Toss]

Hi,
First, are you certain that it is bronze? Many allegedly bronze fittings are actually brass, including those made of "naval bronze" and "manganese bronze."
Second, while bronze is much more fatigue-resistant than stainless, it will harden in time. If this is an old fitting, used regularly, it might need to be annealed.
Third, bronze is less noble than stainless, so a prime place to check for galvanic action is under fasteners.
Fair leads,
Brion Toss