Scubapro MK10 service kit, 10-500-041

[triggerman365]

I purchased a Scubapro MK10 service kit, 10-500-041 to service my MK10. This kit has a red washer as you can see in this photo of the kit



Based on a quick SB search, DA Aquamaster posted the following in a previous threat:

There is a red washer used to seal between the seat and reg body that also ensures the seat stays in place, but reusing that would not result in reg failure and its used to be done with an off the shelf o-ring of suitable diameter which would still work fine.

When I disassembled my MK10, it had an o-ring instead of the red seal.

I noticed the kits from VDH use an o-ring.

Is there any difference? Is one better than the other?

 

[halocline]

No difference, I use an o-ring because I can buy them. The bushing is a little easier to seat and stays in place while you're installing the seat retainer. It does seal HP air from escaping out the hole in the back of the seat retainer, so it has to fit well. I use a duro 90 (013), I think. The original SP o-ring was purple. I would not re-use the plastic bushing, it works like a crush seal.

BTW, there are a few o-rings not visible in your kit that I would replace. One is the 017 around the turret (I thought that one was included) and the two others that seal HP air; the 011 on the yoke retainer, and the 015 on the flange of the seat retainer. Not a bad idea to replace the big body o-ring (117, maybe?) if it has not been replaced ever.

 

[redacted]

I believe the problem with the o-ring (2-012) is it must be seated properly before the seat retainer is installed or it may leak. drop the lubed o-ring in place and then use a socket (I use a 3/8 deep but it is the OD that matters) to press the o-ring into the groove. I purchased a "non-repairable" regulator that some SP LDS could not service with nothing wrong with it other than that o-ring was not properly seated. I have to wonder whether the shop was that inept or just that devious as the owner had replaced his "non-repairable" Mk5 with a new Mk25.

 

[Zung]

Or maybe the original owner used his "lifetime warranty" privilege and got a MK25 for free.
I have at least one where I fitted a Duro 70 o-ring because that's all I have, and it works. It's a face seal, so extrusion is not too much of a problem.

 

[Couv]

Yep, what they said. It's a good policy to replace all internal o-rings and the yoke retainer o-ring. All the port plug o-rings can be inspected and left in place if you're running short.

If I have an orange washer I use it just because there is no other use for it.

The annotated schematic for the MK 10 is available for download at VDH https://backup.filesanywhere.com/fs/v.aspx?v=896b668d5b6172b09c9a

 

[triggerman365]

Well, I shimmed my MK10 with the max number of shims (3) and installed a + hp seat. I also clean out all the silicon grease and replace it with christolube. The IP is 135. I took it out for a dive and it was perfect.

I'm thinking that with 3 shims and +hp seat the IP should be about 145, so maybe the main spring is getting old. So, I'll watch the IP and if starts going south I'll start looking to get a new one.

 

[redacted]

As I understand it, springs tend to get stiffer with age, not softer. (Too bad more things are not like that.) I like to set the IP on my Mk5s (same basic configuration with larger piston) down around 125. Through use the IP will increase. This leaves me a bit more room for IP change before I need to service again.

 

[Couv]

Well done Triggerman.

 

[Slamfire]

Or maybe the original owner used his "lifetime warranty" privilege and got a MK25 for free.
I have at least one where I fitted a Duro 70 o-ring because that's all I have, and it works. It's a face seal, so extrusion is not too much of a problem.

I've had repeated extrusions while using Duro 70 vitons. They work well for a couple of months and then they start leaking thru the hole on the seat retainer. When I open the leaking reg, I've invariably found that the oring twisted/extruded towards the inside, sometimes going so far in that the piston nicks out a little portion of oring. I should've gotten duro 90s, but 70 was all that my local Grainger store had at the time. I use 013 size. Maybe I should try the 012s...? Or could it just be that I'm not fitting them in properly? They work well for about 20-50 dives so I doubt that is the problem. Any way, reused red washers work better for me than the soft 013 vitons.

 

[redacted]

I've had repeated extrusions while using Duro 70 vitons. They work well for a couple of months and then they start leaking thru the hole on the seat retainer. When I open the leaking reg, I've invariably found that the oring twisted/extruded towards the inside, sometimes going so far in that the piston nicks out a little portion of oring. I should've gotten duro 90s, but 70 was all that my local Grainger store had at the time. I use 013 size. Maybe I should try the 012s...? Or could it just be that I'm not fitting them in properly? They work well for about 20-50 dives so I doubt that is the problem. Any way, reused red washers work better for me than the soft 013 vitons.

Oops, I rechecked the numbers and 2-013 is the correct size. I am using duro 70 (or 75) and have had no problem. The only time I saw extrusion like you are describing (reg serviced by an LDS tech) I replaced to O-ring and made sure to seat it correctly. I suspect that may be you problem. If it were truly extrusion, the o-ring should be moving away from the high pressure, not into it.