Mako-Sub pneumatic speargun

[popgun pete]

Some years ago I picked up an old "Mako-Sub" pneumatic speargun. I believe that they are/were made in South America (Brazil?)and bear a strong resemblance to the "Cobra-Sub" guns also made there. The gun is the usual mid-handle, small diameter front barrel type with a black colour scheme and a red plastic, highly contoured finger grip section mounted on the stylish, but rather chunky black plastic mid-handle.

What I am after is some info on disassembling it, particularly the rear pressure chamber as it appears to be very hard to screw off the centre grip section, in fact it will not budge at all. I have removed the rear end cap (it just unscrews for attaching the hand pump) and then removed the rear pressure chamber bulkhead using a pin wrench to engage the two holes provided in it for that purpose. Unlike other pneumatic spearguns of the classic "rear bottle" air reservoir type (e.g. Nemrod) the inner barrel tube does not hold the gun together. The rear of the inner barrel stops well short of the rear end of the gun, so it is the outer barrel or air tank tube that performs the structural element task and consequently it has an internally threaded section at the rear end to engage the "screw in" rear bulkhead. I assume that it is the same story at the front end of the air tank, i.e. a threaded connection to the plastic centre grip section, but something seems to be holding it together. I have learnt in the past that brute strength application often ends up with busted parts, so I am seeking someone else's input on this one before I push on.

Having disassembled and reassembled many pneumatic spearguns successfully I generally know what I am doing, so please no "leave it to the experts" comments.

 

[petar_dj]

post some pics of the partly dissembled gun.

a year ago I was struggling with taking apart my vico jet 110.

the taking apart procedure is straightforward, but due to the fact that your gun has not been taken apart for , say 30 years, all the connections, o rings and threads stick like hell.

here is how i did it:

unscrewed the muzzle (A)
unscrew the black plastic ring (B)
unscrew the 3 screws which hold together the handle (C), remove the handle.
take out the trigger mech.
this leaves you with the inner barrel (in my case 13mm ID) and the air cylinder at the back. this is the point
(if I understand correctly where you are at)
the sealing o ring behind the handle is stuck, preventing you from further progress.

the barrel is screwed into the black plastic part at the end of the gun, which also holds the pump attachment.
this is how i took'em apart:

use a thick cloth, folded a couple of times (so you dont scratch the barrel) and plumber pliers. avoid using a vice so you dont deform the barrel. grab the barrel with the pliers. have a buddy of yours turn the air cilinder in the counter clockwise direction (unscrew) and you should loosen both parts.
lots of luck to you and gripping power to your buddy=)

 

[popgun pete]

Thanks for the response. I will take some photos, but the key difference to what you have described is the grip handle, which is a separate part to the plastic receiver located immediately above it, cannot be removed beforehand as there are no visible screws holding it on.

I am sure that you are right and that everything is just very tight after so many years, however I have to hold onto the plastic receiver, not the forward barrel tube which is sticking out of the front of it. If I grip the forward barrel tube while applying a lot of twisting force then I could crack the barrel tube's air-tight join to the plastic receiver which is moulded around it during production, they are not designed to resist high torsional loads.

 

[strangelove]

Popgun

The guy who makes those gun used be a machinest for the cobra guns, I personally own a couple of those, they break even more often then the cobras, any way, I have not deal with them for 20 years but, I think the barrel is the main element of the gun, every thing else is assemble around it, if I recall, the plastic handle and barrel cannot be take it appart, the air chamber screws on the back on the handle and the muzzle screws on the tip of the barrel, the barrel has an opening for the trigger system (crappy - breaks a lot often shots without pulling the trigger), it has a nylon piston , that shaft needs a little plastic butt.

The trigger system uses a nylon rod, that often breaks, so once it broke on me, of course I found out when I tried shoting a fish, needless to say I try to use the gun as a pole spear did not work too well.

The gun leaks a lot of air but it is also very hard to pump it back, never leave home with the pump (just like your visa card).

When brand new these guns barely worked !

These guns are the main reason I've switch to band guns

If you don't know any thing about fixing pnematics, you should get one of those, you certainly get good on fixing them. The good news is it has very few moving parts !

What is the problem with gun any way ?

 

[popgun pete]

I bought the "Mako-Sub" gun out of curiosity on eBay, it is not a gun for use, although I would certainly like to try it out. I have other "user" spearguns, both pneumatic and band guns. I know a lot about fixing spearguns, I have been doing it for over 30 years, but I have not seen these guns before and have only seen photos of the "Cobra" guns on eBay and the "Cobra-Sub" web-site. The "Mako-Sub" speargun came to me without its spear or hand pump, however I have many pumps from other brands. The gun was bought by the USA eBay seller at a local garage sale, it had been discarded because the piston has no front end on it, just a brass prong with a small ball shape on the end. I assume that the nylon piston (it has a brass inner core) originally had a semi-soft shock absorbing sleeve on the front end into which a ball ended prong on the spear tail was pushed, this is the same approach as that used by the Russian "Seabear", only instead of a ball-on-prong shape it uses a twin tapered cone shape on the spear tail and another on the nose of the metal piston. The deforming and hence energy absorbing plastic sleeve sits in between them and holds the spear in the gun when loaded, but of course the sleeve cannot escape the muzzle when it slams into the muzzle diameter constriction and thus stays inside the gun. Until it breaks up that is and falls out in small pieces! The reason that I came to this conclusion, please tell me if I am wrong, is that the "Cobra" pneumatic spearguns also used a ball-on-prong ended spear tail.

If anyone has a parts diagram for a "Mako-Sub" gun then it would be a big help, as would be a reel, the original owner removed it before disposing of the gun. I can make new spears and may possibly convert the piston and muzzle system to the Mares or Cressi type arrangements using my workshop's machining facilities.

 

[strangelove]

Popgun

Here is the factory Mako Sub - Rio de Janeiro - riodejaneiro.br2.biz but I could not find a web page.

The owner is a jerk

This is a store that may have the parts. These guys are very nice.

New Dive

This will be a good hobby, like repairing a Hugo

 

[popgun pete]

Thanks for those web contacts, I will follow up on them. Attached are some photos of my "Mako Sub" gun. Muzzle to butt it is 103 cm in length. Note that the trigger safety control lever is the red thumb rest on the handgrip, so easy to know that it is definitely "off" when you are in hunting mode. The barrel is high mounted in the gun and not concentric with the rear air tank. Muzzle is just a plastic moulding with no shock absorber incorporated inside it.

 

[Cammo]

Hey Pete,
Nice thread, I see why you bought that gun - very wacky handle, haha:martial
I was wondering (if it is designed to come apart) if a tiny bit of heat in the right place will help get that joint apart, its amazing how loctite instantly gives with a bit of heat, but of course take it easy, I don't want you frying your new gun :head ;-)
I'm about to order a tovarich kit if I can ever get Ramon's bank details worked out!

 

[popgun pete]

Thanks for the suggestion, however I tried heat on it during my previous dismantling attempts, first by letting only the rear tank get hot with the gun out on a table in the sun while the rest of the gun was covered up with a thick towel. That got the tank hot, but not enough to get it to budge (this was on a very hot summer day). I then tried wrapping the tank just behind the handle with cloth which I then soaked with boiling water, that also got the tank nice and hot, however differential expansion did not do the trick then either. I will try the suggestion of getting two people to hang on while twisting it, the tank slips under your grasp even while wearing chrome leather work gloves to increase grip when doing it yourself. I have had the Mako-Sub gun for a few years, I only thought of attacking it again when I saw the posts here on the Cobra-Sub gun, although different companies they appear to be related according to Ted Budion's and strangelove's recent comments.

 

[strangelove]

Pete

When I was working on mine I normally place the handle part on a vise then with a pipe tool would unscrew the chamber.

 

[popgun pete]

I thought a pipe wrench might chew up the smooth anodised surface of the tank. I tried one of those rubber strap type pipe wrenches that plumbers use on PVC plastic pipes, it lacked sufficient grip and slipped.

I contacted New Dive in Brazil, they have the parts listed on their web-site, but I just got an e-mail saying that they have no way of doing exterior sales, which I assume means no foreign sales.

 

[strangelove]

[QUOTE
I contacted New Dive in Brazil, they have the parts listed on their web-site, but I just got an e-mail saying that they have no way of doing exterior sales, which I assume means no foreign sales.[/QUOTE]


That would be the tuff part, let me contact them to check what is the major issue, if it shipping or paying.