MK25 bubbles from turret swivel

[rthorntn]

Thanks all.

Does anyone have high resolution images of all the MK25 parts and the names, the round piece of white plastic (see photo) on one end of the piston assembly, is that supposed to have a flat section, it exposes the o-ring a bit and doesn't look quite right?

Check it with a straight edge. Doesn't take much to cause a leaky seal.

I checked the turret bolt with a steel ruler, it looks OK.

I believe there should have been a small white/plastic/nylon thrust washer in there, at least there is in the MK20. That still there and not damaged?

It's there, it looks OK.

The turret will have a bit of play. Change the o-ring, light lube, assemble and see if it still leaks. If so check the hose fittings.

I have the OMS O-Ring Kit, can I use an o-ring from this kit or do I need to get another one, also what lube(s) do I use inside the MK25, I have CHRISTO-LUBE MCG 111?

 

[Couv]

Rthorntn: Thanks all.

Does anyone have high resolution images of all the MK25 parts and the names, the round piece of white plastic (see photo) on one end of the piston assembly, is that supposed to have a flat section, it exposes the o-ring a bit and doesn't look quite right?

Yes, that is known as the "air access flat"

I checked the turret bolt with a steel ruler, it looks OK.

Have a good look at the threads of the turret bolt and turret itself with a 10x or greater magnifying glass. Check for any distorted or stretched threads.

It's there, it looks OK.

I have the OMS O-Ring Kit, can I use an o-ring from this kit......yes, if it is the same size and durometer........ or do I need to get another one, also what lube(s) do I use inside the MK25, I have CHRISTO-LUBE MCG 111?

Christolube is fine.

 

[Tbar]

Does anyone have high resolution images of all the MK25 parts and the names

Have a look here http://www.frogkick.dk/manuals/scubapro/Schematics/1. Stage/

I have the OMS O-Ring Kit, can I use an o-ring from this kit or do I need to get another one, also what lube(s) do I use inside the MK25, I have CHRISTO-LUBE MCG 111?

The o-ring is part no 010-50-162 its a 2-017 durometer 70

 

[redacted]

If you are getting bubbles from between the turret and the ambient chamber the cause is almost surely the failure of the o-ring or one of the mating surfaces. I suspect the tumble has compromised one or more of those parts. A small distortion of one of those metal surfaces may be very hard to detect.

 

[rthorntn]

Thanks everyone, I had a look over everything with a 20x jewellers loop, the threads on the bolt look fine, its pretty much impossible for me to assess the threads inside the turret, what would be classed as a mating surface, would metal on metal ever be a mating surface, there are small "nicks" and scratches on the metal to metal surfaces on the cap and swivel?

Does anyone have a good place to get o-rings like the 2-017 durometer 70 in Australia?

 

[Couv]

Contact any o-ring supplier and ask them for a -017 FKM (Viton) or EPDM duro 75 or 70 o-ring.
O’ring Sizing « Sealing Australia or pull one out of the kit you have that fits on the turret. It should stretch only a tiny (1-5 percent) amount when it's in the groove.

 

[rthorntn]

Thanks couv so these:

Viton Rubber Orings Size 017 Price for 25 pcs | eBay

 

[Tbar]

I use SIL in Brisbane, but they are national (Sydney details below). I buy 100's to make-up kits. They do post/courier.

Or you can just go to a 'local' hydraulic/bearing shop who should have the o-ring on the shelf. For example Industrial and Bearing Supplies | Home

SIL Sydney Branch
Unit 3, 163 Prospect Highway
Seven Hills 2147
Sydney NSW
Phone: 02 9838 4033
Fax: 02 9838 4099
Email: sydney@sealimports.com.au

 

[Couv]

Thanks couv so these:

Viton Rubber Orings Size 017 Price for 25 pcs | eBay

Yes,

But I think the MK20/25 uses that particular size in only one place, and that is the turret; so you'll have enough to last you a few lifetimes should you go for that deal. You might start a new thread, similar to one we had before (Oring swap,) asking for an o-ring exchange or swap. I'm pretty sure one of your fellow countrymen can come up with a few for you. If not, PM me with a snail mail address and I'll a send some your way.

 

[redacted]

Another option would be to find a metric o-ring 17mm ID by 2mm thick. A 2-017 is 17.17mm ID and 1.78mm (11/16 inch by 1/16 inch) so that would also give you just a bit more material to make the seal but is close enough that it should fit with no problem.