• Welcome to the DeeperBlue.com Forums, the largest online community dedicated to Freediving, Scuba Diving and Spearfishing. To gain full access to the DeeperBlue.com Forums you must register for a free account. As a registered member you will be able to:

    • Join over 44,280+ fellow diving enthusiasts from around the world on this forum
    • Participate in and browse from over 516,210+ posts.
    • Communicate privately with other divers from around the world.
    • Post your own photos or view from 7,441+ user submitted images.
    • All this and much more...

    You can gain access to all this absolutely free when you register for an account, so sign up today!

Mares Minimini Sten Air Leak Help

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

NateKirby

New Member
Sep 5, 2021
3
0
1
48
I was just given a Mares Mininini Sten that is leaking air. I took it all apart, cleaned it, lubed, and reassembled. It is still slow leaking around the nose cone/muzzle. I plan to change the O ring on the plastic piston. Anyone know if I'm supposed to put anything on the threads of the nose cone before tightening to help make a seal? Any other advice? The air is seen leaking out of the vent holes in the cone.
Thanks so much for any input!
 

popgun pete

Well-Known Member
Jul 30, 2008
4,282
1,194
353
You need to change the "O" ring that sits on the inner barrel that presses against the rear of the nose cone. Put some grease on the end threads when you slide the "O" ring over them to prevent any scratching of the "O" ring by the thread peaks. You should also change the piston seals. You can buy a kit that has the necessary rings and seals. Do the job right and you only have to do it once so I suggest you replace all of the seals.
 
Last edited:

NateKirby

New Member
Sep 5, 2021
3
0
1
48
You need to change the "O" ring that sits on the inner barrel that presses against the rear of the nose cone. Put some grease on the end threads when you slide the "O" ring over them to prevent any scratching of the "O" ring by the thread peaks. You should also change the piston seals. You can buy a kit that has the necessary rings and seals. Do the job right and you only have to do it once so I suggest you replace all of the seals.
Wow, thanks so much for the insight! I really appreciate you taking the time to help me out. I changed the O ring on the piston and that seemed to help a bit. I'll do as you said and change the one on the barrel for now until I can order the full kit.
If I can ask 2 more questions, what type of oil should I put in the gun, and how much on this little Sten? It is the 16 inch minimini gun.
Thanks so much!
 

popgun pete

Well-Known Member
Jul 30, 2008
4,282
1,194
353
Fork oil for motorcycle suspensions is ideal, the SAE 10 grade. Autospares shops have it, you can buy it anywhere in small plastic squeeze bottles.
Mares Sten oil quantity.jpg


Note the 58 cm gun is the Ministen, this table was in a Mares Service document and the Miniministen is only the 42 cm gun, not the 58 cm. Someone goofed typing the table.
 
Last edited:
  • Like
Reactions: Pinniped72

NateKirby

New Member
Sep 5, 2021
3
0
1
48
Fork oil for motorcycle suspensions is ideal, the SAE 10 grade. Autospares shops have it, you can buy it anywhere in small plastic squeeze bottles.
View attachment 57486

Note the 58 cm gun is the Ministen, this table was in a Mares Service document and the Miniministen is only the 42 cm gun, not the 58 cm. Someone goofed typing the table.
Thanks so much for this info! I found a manual with the air pressure, but it didn't have the oil quantity. I truly appreciate your help! Have a great day!
 
DeeperBlue.com - The Worlds Largest Community Dedicated To Freediving, Scuba Diving and Spearfishing

ABOUT US

ISSN 1469-865X | Copyright © 1996 - 2021 deeperblue.net limited.

DeeperBlue.com is the World's Largest Community dedicated to Freediving, Scuba Diving, Spearfishing and Diving Travel.

We've been dedicated to bringing you the freshest news, features and discussions from around the underwater world since 1996.

ADVERT