Question Scubapro MK20 swivel retainer failure questions.

[Diver Stan]

I dive and maintain Scuba Pro MK10s MK10+ and MK20s and was servicing an MK20 when the swivel retainer cracked off while I was torquing it to the spec for brass of 35 lbs/inch. I had that sick feeling trying to acheive this very low torque before the retainer separated.

I am glad that torquing identified this problem, because a cracked or weak retainer would result in a catastrophic failure underwater.

I found a replacement part online, but the retainers are no longer available from Scubagaskets. This retainer is compatible with the MK10s and MK20, so common.

Have you heard about this kind of failure? Makes me want to change out all the swivel retainers for the other regs when I service them.

Do you know of another source for these retainers?

Swivel retainer for Scubapro as part no: 10.500.104, Also the nylon washer for MK20 swivel as part no 01.060.500.


Thanks,

Stan

 

[p_kos]

The brass ones were prone to failure if torqued too much. Someone may have over-torqued yours previously. The replacement retainers are stainless steel.

 

[Diver Stan]

Thanks, I obtained a second retainer ScubaGaskets. These seem to be stainless, but not marked and I can't tell. I am torquing these to the lower setting which seems to work fine.

I really need to obtain a new under the table contact with a SP rep around the SF Bay Area.

Cheers,
--Stan

 

[happy-diver]

The crew on here organised to get some stainless ones made about ten years ago

 

[Joris Vd]

i've had one crack on me at 15 lbs/inch, . Brass Fatigue is a real thing.
There's plenty of mk10's and 5's where the brass retainer was never changed and these are quite dangerous nowadays.
So it is definitely something to check if you dive older turret first stages.

I just bought a set of ss retainers from vintage double hose and swapped all out on my mk5's and 10's to not risk anything.

 

[Couv]

The crew on here organised to get some stainless ones made about ten years ago

We had those made for the MK5. They will not work in later models.
@Diver Stan You'll have to scratch the surface to determine if you have a SS or brass retainer. (Actually, I hope someone has a better way.)

Edit: @Joris Vd Where did you obtain the MK10 retainers? I do not think the VDH retainer will work on anything other than a MK5

 

[Joris Vd]

We had those made for the MK5. They will not work in later models.
@Diver Stan You'll have to scratch the surface to determine if you have a SS or brass retainer. (Actually, I hope someone has a better way.)

Edit: @Joris Vd Where did you obtain the MK10 retainers? I do not think the VDH retainer will work on anything other than a MK5

My bad, it's been a couple of years, so I just assumed they all came from the same shop.
The mk10 ones I bought somewhere else, but I'd have to check. Might have been my lds, but I'm not sure anymore.

In my experience alot of the older dive stores als have huge trays of spares for older models. Might be worth having a listen there as well.
If you need any steel turret bolts, I could see how many I have left and send them to the US in a letter . I only use two mk10's atm for my stages anyway.

 

[axxel57]

i've had one crack on me at 15 lbs/inch, . Brass Fatigue is a real thing.
There's plenty of mk10's and 5's where the brass retainer was never changed and these are quite dangerous nowadays.
So it is definitely something to check if you dive older turret first stages.

I just bought a set of ss retainers from vintage double hose and swapped all out on my mk5's and 10's to not risk anything.

The change of brass retainers to SS Retainers must have happened between '99 and '01, but I couldn't find any Technical Bulletin about it, even when I'm sure I had one.
My MK10 schematics from '99 are in TIF., don't know how to upload them, they give already the new order number ...104, instead of the '97 schematics, which still use the ....103. The torque should be 4 to 5 NM, so they were still brass.
The Schematics from '01 give the different torques for the brass and SS Retainers, but use also the order number ...104 for both types.

 

[p_kos]

We had those made for the MK5. They will not work in later models.
@Diver Stan You'll have to scratch the surface to determine if you have a SS or brass retainer. (Actually, I hope someone has a better way.)

Edit: @Joris Vd Where did you obtain the MK10 retainers? I do not think the VDH retainer will work on anything other than a MK5

SS ones look duller/matte compared to the shiny chrome over the brass ones. I’m not sure if this is always true so scratching it might still be necessary.

 

[halocline]

I have never heard of brass retainers for the MK20 and frankly I would be shocked to see one. The change from brass to stainless steel was made in the MK10, which is two generations earlier than the MK20. I think the MK20 was first produced around 2000 (I'm not sure of that) so I guess it is possible that some of the very earliest ones had brass retainers. Maybe I'm wrong about the timeline.

I still have at least one MK5 that has a brass retainer but all of my MK10s have steel ones. I have (I think) one of the vdh MK5 SS retainers left and maybe someday I'll install it on that MK5, but the brass retainer looks perfectly fine to me.

I also would be very surprised to have one crack at such a low torque if there was no visible damage under inspection with a magnifying lens. But I guess it's possible. Those brass retainers worked very well when not over-torqued (or maybe damaged in some sort of impact, like a tank falling over with the reg attached) for many years. I understand the desire to change them out because if they break in use, it's catastrophic, but I think it's very rare. I sometimes use MK5s in cave diving and for those I have the SS retainers installed.

I've seen early MK5s that used just a circlip to hold the turret in place.