One cautionary note to the "if it ain't broke, don't fix it" mantra...
I have a SPEC-booted Scubapro Mk10 that I just took to Cayman Brac for a week of diving that hasn't been serviced in over ten years.
View attachment 798434
It started here: thread
DIY SPEC Boot .
IP locks up crisply in the high 120's and has never budged.
But I lied...
Every year, I remove, clean and replace the yoke bolt. The rest of the mechanism has never been touched.
Why do I do this?
It used to be that manufacturers used a HP o-ring at the collar of the bolt threads:
View attachment 798426
But they had a higher incidence of extrusion, so most mfrs have gone to end o-rings at the bottom of the DIN or Yoke bolt.
View attachment 798427
The problem with the change is that the collar o-rings protected the bolt threads from salt water that otherwise percolates in under ambient pressure on a dive. That salt never gets rinsed out, and gradually causes verdigris corrosion which locks the bolt to the reg body. In contrast, an end o-ring offers no such protection.
I just recently serviced three Poseidon XStream sets for a customer who "got them off eBay" for a steal. And indeed, they all locked up nicely within spec. The XStream is the best diaphragm design in the world, IMO.
But he ended up spending an extra $90 on two new DIN bolts because I literally had to deface them with a pipe wrench to disassemble them from the reg body. The U/S didn't work; the freezer didn't work; I bent my custom wrench on the thin flats of the bolts (as well as spalling the brass). Finally, they sat for 4 days after drippng Aero-Kroil into the threads, and a pipe wrench did the trick.
Poseidon switched from a collared o-ring on the 2960, to an end o-ring on the XStream. Arrgh!
So I lied about my Mk10. The internals haven't been serviced in 10 years, but the bolt comes off
every year.
If it ain't broke, maybe don't fix it.
Except the yoke or DIN bolt. Service it every year, because you can't see that it really needs it.