The Boss is Back!

[rodrigo571]

Thanks for the forum and all who post good info. and tips!

My Fx Boss 30 cal. had a leak and I could repair it! Now please don’t laugh about me, I’m not an expert servicing PCPs so this is a big achievement for me...

The leak was not obvious. It was a slow leak, about 5 BAR per day. Finally I found it was leaking through the vent hole of the regulator. Opened it, replaced the external orings of the regulator, which looked damaged (luckily had an oring kit!), assembled and filled with air. After 1 day it seemed keeping air. Then went to the chrony, numbers were good. Filled again and waited a week. It kept all air. Tested, it works as it should. Very happy.

Perhaps in these times the newer airgunners don’t know or don’t remember that it was a big HIT when the Boss first came out some 10 years ago. A 80 fpe gun, giving more than 40 regulated shots per fill, good trigger, flawless multi-shot, with a very decent noise suppression right from the factory. This was something not seen before. I bought mine new in 2013 and loved it, at 25 yards it stacks pellets all day.

So the Boss is back and ready for rock & roll!

 

[elh0102]

IMO, the best platform ever made by FX. I have a Royale 400, and it has been perfect. I installed the Boss match trigger, which was a challenge since FX ships it in a plastic bag with all the pieces unassembled, and no instructions. Ernest Rowe has a good video that saved the day. But I digress. The Boss/Royale platform with the original solid ST barrel is essentially everything the current FX rifles are not; i.e., simple, robust, totally dependable, almost never needs cleaning.
What it lacks is all the doodads and accessories that feed the company sales and the service department. If I were a shareholder I would like the business model, as a shooter I have no interest. But that's just me. Keep that Boss and love it!

 

[Ranchibi]

Very satisfying to re-seal ones own PCP and IT HOLDS AIR! Good work there, beautiful Boss.

 

[rodrigo571]

Thank you elh0102 & Ranchibi!!

I was out of the hobby for some years, and just returned. Found most of my PCPs empty and not capable of holding air. I am in a “campaign” to recover them. Feels good to bring one of them to life.

I don’t know much about the newer Fx guns. I read here and there, that they are totally adjustable, with many flavors, many caliber options, etc. The offer looks nice.

... The Boss/Royale platform with the original solid ST barrel is essentially everything the current FX rifles are not; i.e., simple, robust, totally dependable, almost never needs cleaning...

Wow. And I thought the Boss was “complex” because it has a regulator... Gulp!... I agree: Simple is better.

 

[Feinwerk]

Congratulations on fixing it yourself! It gives you quite the feeling of satisfaction and sustainability.

 

[rodrigo571]

Congratulations on fixing it yourself! It gives you quite the feeling of satisfaction and sustainability.

Thank You Feinwerk!!

 

[GrimJay]

Good job. I need to reseal mine, was there a video you used? I have an o ring set, not sure how to go about it. Thanks for any input it would be greatly appreciated.

 

[rodrigo571]

Hi!

I am not an expert. Assume you are not one also.

I didn’t find specific Boss leak videos on Youtube (there is a good one about the regulator). The Boss platform is very similar to the Royale 400, Royale 500 or Bobcat. So you can search any of those guns and find something useful. Also, there’s plenty of good info. right here on the forum.

If you don’t have the schematics yet, get them here:

https://fxairguns.com/wp-content/uploads/2019/07/Boss-190730.pdf

To degass the gun, unscrew A20, just a little bit. This way you will degass both, the bottle and the regulated chamber.

Then you must remove the barrel. There are 3 screws on top of the action block for that.

Then you can remove the quickfill F9 and after that, the bottle and the F1 part.

After removing the bottle and F1, you can access the regulator.

You can also remove the valve cap A34 and access the valve parts.

Before disassembly, it is best to have found the leak. Fill gun with air and use soapy water or a special leak detector fluid.

Common leaks are in the quickfill valve (oring F8), the hole of A20 (oring A19), the pressure gauge (oring A23) and the vent hole of the regulator, which is a hole just a couple millimeters away from the hole of the pressure gauge. Also the valve could have a problem, in that case air would escape through the barrel.

If the leak is in the vent hole of the regulator, then you have to change the regulator orings (rebuild the regulator). As I found in my research, those orings are:

2 outer orings (they are the same size): 11.9 x 2.62 NBR70 (Fx part 17047)
2 Inner orings:
“high pressure” 2.9 x 1.78 NBR70 (Fx part 15016)
“low pressure” 6.07 x 1.78 NB70 (Fx part 15015)
1 oring on the metal seat 7.5 x 2.0 NBR70 (Fx part 19225)

However, in another source, some of these orings are slightly different:
2 outer orings (they are the same): 11.6 x 2.4 (Fx part 5109)
1 oring on the metal seat 7.66 x 1.78 (Fx part ??)

Perhaps both versions will work.

The standard “seal kits” that I found, do not cover the regulator orings. Those can be bought separately...


Hope this helps.
Good Luck!

 

[GrimJay]

Sweet! I really appreciate all the valuable information, it’s been sitting in the safe dead for way to long. I’ll have to try and find the leak and check my oring set. Thank you very much for taking the time to write all that down. Above and beyond sir!

 

[rodrigo571]

Sweet! I really appreciate all the valuable information, it’s been sitting in the safe dead for way to long. I’ll have to try and find the leak and check my oring set. Thank you very much for taking the time to write all that down. Above and beyond sir!

You are wellcome!

PS: Take ALL advice in the internet with a grain of salt. Use common sense. Look for second opinions. Be safe!

 

[Florida_Man]

Congratulations. Now shoot up all those old pellets!

 

[rodrigo571]

Congratulations. Now shoot up all those old pellets!

Yes. You noticed!

Thanks.