Help servicing Nemrod Corsario

[spoolin01]

Help servicing Nemrod Bucanero

I picked up a Bucanero (I first posted this was a Corsario, but looking at the pics at scubasworld.com, I think it's the Bucanero) last week from a local guy who said he bought it from a shop here but never got it working. When I unscrew the rear cap, I'm looking straight down the back of the barrel, and there's a threaded nub sticking out of the plastic cap. The nub has a hole in the center, yet the cap is a blind end. That seems odd. At first I thought something might be missing, but after looking at Djohn's pictures in this thread, I think maybe the rear valve is stuck in the cap and comes out when the cap is unscrewed. Is that right? I guess I just need to gently grip the threaded nub and twist on the cap, is that also right? Is there a better way? The cap is split as well, I'm hoping that doesn't really matter.

I've had the nose cone and knurled nut off, but haven't been able to figure out how the rubber-coated section comes off - it just twists on its metal tube around the barrel. I also haven't pulled the piston.

Can someone give me some tips on further disassembly? I gather rehabbing the piston may be a chore, but I'd at least like to get the gun apart and look at everything to see if servicing looks doable.

 

[popgun pete]

Air pressure cracked the rear plastic cap, that is why it is split. The inlet valve leaked, which looks to be missing. Your gun is a "Bucanero", the "Corsario" had a power regulator knob at the rear. Both are Nemrod "Silver series" guns. Unscrew the muzzle, then pull the rubber grip section off and undo the knurled metal ring behind it. Take the plastic handle off by undoing the transverse screws, then undo the vertical screws that hold the metal frame that the plastic handle fits into onto the outer tank. This frees up the thick metal shroud casting that surrounds the inner barrel in the centre of the gun, the vertical screws penetrate the tank and hold all these elements together. The rear bulkhead screws off with the inlet valve body. Like all air guns the inner barrel is the structural element holding the gun together and is threaded at either end. Exceptions are guns with threaded outer tanks, then the inner barrel can be non-threaded at the rear end as it does not have to hold the gun together as the rear tank forms part of the gun structure. The "Silver series" Nemrod guns have plain tube tanks.

 

[spoolin01]

Thanks, I'll take another look at the front section. On mine, there was a knurled nut immediately behind the nose cone, forward of the rubber grip, which appears to be formed around a thin aluminum tube that rotates freely about the barrel, but I haven't been able to move it laterally. I'll try harder.

For the back end, in the pics Djohn posted, it looks like the fill port and pump fittings are the reverse of the current rear-handle design, with a male fill port and female pump end. If that's so, then it appears the fill port/valve on my Bucanero is still stuck in the plastic end cap, is that right? It looks like I need to grip the threaded back end of the port insert, and twist on the cap.

 

[popgun pete]

Thanks, I'll take another look at the front section. On mine, there was a knurled nut immediately behind the nose cone, forward of the rubber grip, which appears to be formed around a thin aluminum tube that rotates freely about the barrel, but I haven't been able to move it laterally. I'll try harder.

For the back end, in the pics Djohn posted, it looks like the fill port and pump fittings are the reverse of the current rear-handle design, with a male fill port and female pump end. If that's so, then it appears the fill port/valve on my Bucanero is still stuck in the plastic end cap, is that right? It looks like I need to grip the threaded back end of the port insert, and twist on the cap.

The ribbed black plastic end cap should have nothing inside it, so as you say the rear valve body is still in the cap, it just screwed out of the inner barrel tube instead of the cap screwing off it.

 

[popgun pete]

The black circular band of a slightly different shade on the photo of the removed tail cap is a rubber seal with an angled front face pointing into the interior of the cap. The seal is there to keep water out of the cap when the gun is underwater as the interior of the cap is not meant to be pressurized. A leaking inlet valve will tend to create pressure in the cap over time and that is why they split, I had to replace mine for that reason.

 

[spoolin01]

If these caps were available, I'd consider replacing it but I expect I'll have to try gluing it.

I finally got the gun apart. One of the handle screws was stuck in place and I half bunged the overly narrow screw slot in the overly soft screw head before noticing that the nut was moving, just not the screw. I was able to grip the nut and undo it so I could drive the screw out with a punch.

Oddly, the draw bar running back from the trigger is not aligned radially with the sear setup. I haven't tried going any farther, but if those screws in the trigger and sear housings are just set screws, as would make sense, should I rotate one or the other (the trigger group?) to align them?

The front rubber-covered tube, ahead of the tank, was being held in place by an o-ring jammed in the forward threads. After removing that, things began to come apart easily, aside from that one screw.

The external cap o-rings look OK, but the internal one in the front cap got shredded pulling the barrel out, and obviously the piston needs full new togs. I've been looking around at faucet washers and spring seats, and various online seal supply houses. I'm also asking scubasworld.com for some help evaluting which current piston cup seals might be workable for this, a Cressi Mach 1.1, and a ScubaPro Magnum. Some things look worth trying, but I haven't yet taken any measurements to narrow down the field.

Has anyone tried the faucet washer suggestion made regarding these Nemrod pistons? They seem quite a bit stiffer than the original type, and a wholly different design, but one that's commonly used to seal hydraulic pistons, so I don't know why they couldn't work if the fit was good.

The gun projects have taken a back seat while I organize my workspace (push things farther into the 8 corners and edges of the garage) to make room. I'll continue to post as progress eventually resumes.

 

[popgun pete]

The Nemrod rear caps in yellow will fit, they are the same cap used on the later mid-handle models with slim front barrels. I used one of the yellow caps until I found a black cap for the gun to replace the original cap which split. The inner barrel tube can be rotated in the cast aluminum shroud section that encircles the inner barrel in the centre of the gun, from memory a set screw holds it in position once the parts are properly aligned. Someone in the past probably twisted the inner barrel and it rotated out of position, that is why it is not properly lined up now. It may have been slightly out from the factory, the guns were assembled in a "close enough is good enough" manner, if the gun worked then it got a tick to pass inspection. The "O" ring jammed in a thread sounds like a later "fix" by a previous owner, probably because the inner "O" ring was damaged in the front pressure bulkhead and was slowly leaking air, so they added this extra seal to stop air working out along the screw thread. I tried that "fix" myself, but ended up replacing the bulkhead "O" ring once I realized that it was the culprit.

It sounds like the faucet washers work as the guy who posted about it should know. You may be able to obtain a genuine piston seal from the guy who started this thread http://forums.deeperblue.com/pneumatic-spearguns/83802-nemrod-comando-speargun-parts.html, he seems to continually be able to find new old stock to keep his guns going. The inlet valve is another area to consider, it uses a fat section small ring that seems to be squashed nearly flat, not being able to replace it sidelined my gun.

The rubber line wrap hooks can tear off, they don't last forever, especially the one in front of the grip, as the rubber gradually deteriorates with time. Rubber muzzle features absorbed knocks and bumps and were OK while you could buy replacements, but their non-availability meant either something else had to be substituted or the guns retired.

These "Silver series" guns were good in their day, but unless you really need a mid-handle layout there are much better guns around now.

 

[spoolin01]

I was pleasantly surprised at the condition of that forward grip, or whatever it is. I'll have to inspect it more closely, but it looked supple and intact.

I don't know what it is, but I have an affinity for these pneumatic guns, and really like the vintage ones. Maybe it's because they kind of harken back to the 50s/60s space age styling I grew up with. Maybe it's because the modern ones are all cookie cutter and fairly featureless. I only have a handful of any kind, but I've enjoyed taking the modern ones apart and fixing them up, simple as they are. For the first time, lingcod season will stay open through the winter for spearfishermen here. I have an idea to get a picture of myself with a big ling taken with this gun.