Question What causes a B2 first stage o-ring failure

[Reef Madness]

I’m getting 1 dive between failures (4 failures so far) and am pretty sick of it. Any ideas what could be causing a persistent 1st stage o-ring failure? This started after the reg was serviced. Was something missed?

 

[L13]

Which o-ring is failing? Details? pictures?

 

[Reef Madness]

I just found a drawing on a similar scuba board post. That post was to identify a leak, but I need to understand why that o-ring continues to fail.

 

[BoltSnap]

Air leaking from the yoke retainer? Most likely the connection was tightened to specs.

 

[207diver]

Who is replacing the o-ring? You or your dive shop? Is it the correct o-ring? You need to be careful that the o-ring doesn’t fall out of place when assembling. If the yoke retainer is properly torqued and the o-ring is the correct size and properly installed it should really never fail.

 

[Reef Madness]

I haven’t done it myself. 2 different shops. I’m starting to think the problem was never the o-ring. What else would cause a leak in the same area but appear fixed until the 2nd use?

 

[Fibonacci]

My first thought was an incorrect Duro o-ring (70 vs 90) with it then extruding shortly afterwards.
Do you have a pic of one of the failed o-rings you could upload?
Failure modes usually have fairly distinctive features...

https://promo.parker.com/promotionsite/oring-ehandbook/us/en/ehome/Failure-Modes

However if both shops are using the correct OEM Atomic service kit it is more likely to be physical damage to either the Yoke Retainer sealing surface (dropped?) or the inner sealing surface of the Body (scored by a careless tech?)

 

[davehicks]

My first thought was an incorrect Duro o-ring (70 vs 90) with it then extruding shortly afterwards.
Do you have a pic of one of the failed o-rings you could upload?
Failure modes usually have fairly distinctive features...

https://promo.parker.com/promotionsite/oring-ehandbook/us/en/ehome/Failure-Modes

However if both shops are using the correct OEM Atomic service kit it is more likely to be physical damage to either the Yoke Retainer sealing surface (dropped?) or the inner sealing surface of the Body (scored by a careless tech?)

That's what i told him in the other thread. Low duro oring. Apparently he wants a different answer?

 

[Reef Madness]

Don’t know you or what you’ve said before. Better off without your two cents.

 

[Tanks A Lot]

You need to be careful that the o-ring doesn’t fall out of place when assembling.

This is probably the right answer. It's best if the technician holds the yoke nut upside down, pointing the O-Ring towards the sky when assembling. Twisting the yoke nut and having the O-Ring point towards the floor can make it fall out of place during assembly.
A picture of the O-Ring will confirm this easily.

70, 80 or 90 shore will not matter in this O-Ring, although I suspect that they will be using a 90 shore O-Ring in that area. This O-Ring is wedged into place securely when the nut is torqued to specifications.

Another possibility is a damaged regulator body or damaged yoke nut. Both parts can easily be damaged by an overzealous technician tightening far beyond specifications. Inspect both parts for visible damage or distortions.