FX Royale 400 leaking, giving me fits

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bchannell

bchannell

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Nov 1, 2020
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Parkersburg, WV USA
I have a used 400 and it's leaking. I've had it apart several times and changed all the orings, and it just keeps on leaking.
So far I've put all new orings in it, even internal reg orings and it still leaks.
* it leaked down the barrel, so I replaced all the firing valve orings, and the seat oring
* it leaked out the reg vent, so I replaced all the oring internal and external on the reg
* it leaked at the gauge threads, so I replaced the seal under the gauge
* for good measure I replaced all the orings on the fill adapter

Now, I can't really tell where it's leaking, but it's leaking quite a bit.
How do you guys find leaks, I had to slather the whole action with leak detect solution so as to keep moisture out of the system, but I'm almost at my wits end.
Please give me an idea of how to find leaks with liquid solution. I've used it on the seams at the bottle etc, but don't want to douse the whole action with it, unless someone says it wont' hurt anything.
Ordering from FX is a problem too, if I don't get it right the first time, I have to wait nearly a month to get an order shipped again, whew! So, I just ordered everything I could possibly think of the last time and am still waiting on my order to arrive two weeks later.
Any suggestions would be greatly appreciated.
 
No I have not checked the stock screw housing. THANKS I had missed that one! I'll check it now.
Here's my methods so far.
1) I removed the moderator, and took electrical tape and taped the holes in the adapter for the moderator up and put a balloon over the end of the barrel. NO leaks down the barrel.
2) I need to check the front oring on the firing valve that can leak to the outside of the action next
3) I need to recheck the orings on the reg, there seems to be some confusion over the correct size.
4) the gauge may be leaking internally but I know it's unlikely, it's not in the best condition.
5) fill valve is not leaking at the inlet, and I need to check the oring on the fitting itself
6) fill valve, tank adapter will need rechecked
7) stock mounting bolt housing oring

Things I've ruled out
1) internal reg orings, the hp and lp can leak out the vent, but I'm pretty sure no leaking at the vent, same with external orings
2) firing valve seat and rear oring

So i continue.
]Thanks for all the advice!!!!
 
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As suggested above you could dip the whole unit under water but must be meticulous about drying it out afterwards (hair dryer). I'd also rub it down with Ballistol or the like to protect it. Definitely do what Ed (elh0102) said & check the stock screw housing. Unscrew slowly & replace the small o-ring on the threads. I've never had a leak on any of mine (Bobcat, Boss, Royale) behave that way. Only had one leak ever & that was at the pressure gauge, an easy fix.
BTW, remove barrel before dipping it. There are 2 external o-rings on breach end of barrel. Mine held up without needing replacement when I pulled my barrel. Make sure to lube them with silicone before reinstalling barrel.
 
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Roachcreek said:
Sounds like the valve seat has been damaged.

AOA will resurface the valve seat, it was probably damaged by shooting it down to degas. That can be a diy project by using a large drill bit to resurface the valve seat.

Regards,

Roachcreek
Click to expand...

I can't detect any leaks out the barrel with a balloon on it with the moderator removed, so I'm doubting it's the seat.
I did redo the stock screw oring, so we'll see what happens there. I 'thought' i detected a hiss when I first put a wrench on it, but you know how that goes, could have been my imagination and me wanting to believe that was it, :)
 
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bchannell said:
I can't detect any leaks out the barrel with a balloon on it with the moderator removed, so I'm doubting it's the seat.
I did redo the stock screw oring, so we'll see what happens there. I 'thought' i detected a hiss when I first put a wrench on it, but you know how that goes, could have been my imagination and me wanting to believe that was it, :)
Click to expand...
Regarding the stock screw housing, if there is any air in the plenum you will drain it when you loosen the housing. That is probably what you heard when you first turned it. It still could be the source of your leak, but hearing air escape there is normal when loosening that piece.
 
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Did some group shooting to see how it does. Well, these are the 10 shot groups at 30 yards with JSB 15.89gr domed.
IMG_20230531_130237736_HDR.jpg


IMG_20230601_164519811.jpg
 
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