FX Slow leak & regulator pressure equalising

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monstr2

Member
Jul 13, 2021
16
2
Hp, Singapore
My Impact Mk 2 pp has started to leak at a rate of about 3 bars a day the pressure has come down from 200 bar to 145 bar today.

When i try to fill the gun the regulator pressure goes up to the same pressure as the tank pressure.

I have only shot about 1000 pellets with my Impact although i turned the reg up to 220 bar at one time to get birds to explode.

Can someone please tell me how i can repair the gun to sort out the problem?

Thanks in advance!
 
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Trucker3573 said:
Yeah probably damaged the regulator. I would suggest going on YouTube and watching as many videos as you can about tuning. Will help with having a general understanding about how it works. I can assure at 220 bar you probably not only damaged the reg but your shot speed was actually much slower.
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Really? I thought increasing the reg pressure was the only way to get more fps?
 
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jps2486 said:
My 4 year old Crown MK2 started to leak from the regulator and behaved about the same as you describe. A good friend helped me rebuild the reg by replacing all the O rings. No leaks now. This is typical of FX rifles.
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I rebuilt the reg in my FX Dream tac compact some time back.

I also noticed just now that the small hole in my Impact reciever is leaking air maybe its the regulator after all.
 
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monstr2 said:
Really? I thought increasing the reg pressure was the only way to get more fps?
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Only to a certain point. As you crank up the reg the valve becomes harder to open due to the higher pressure behind it. It therefore needs a harder hammer strike to open it and effectively utilize that higher pressure to get higher velocities. An impact with stock internals even with the hammer spring maxed out completely will not have a hard enough hammer strike to open the valve anywhere near 220 bar. I think a stock impact stops producing gains at like 150 bar. To go above that you need heavier hammers and stiffer springs.
 
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To the OP. You do not know what your doing and therefore damaged the regulator. Education is always expensive. Working on a leaking regulator is very difficult, even for experienced people. You should change at least the "O" rings, but you have damaged the the sealing surface of the regulator piston. I highly suggest getting a new one to start. 3M sells special polishing cloths. These very fine abrasive cloths are the ONLY things to use on the mating surfaces and the polishing should be done on a lathe. I will point out that few repair facilities are good at this task. There are a few YOUTUBE videos on this process. You will need good luck.
 
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Meh, get the sizes of all of the 0-rings in the thing for the reg, go to the 0-ring Store buy a bunch, way cheaper than a dumb kit, get a good brass o-ring pick kit and a nice needle, that's for the one buried down in the hole, replace o-rings, if you don't have the new brass pistons, get them, less heart ache. If you do have the new brass pistons look at the little Delrin piece in the middle, is it concave (bad) or convex/flat (good) I'll bet on concave due to over pressure. Replace ALL of the o-rings, they're cheap because you now have LOTS of them, lube with a good oil, doesn't need to be silicon, regular synthetic won't explode in the gun. I've found that those little suckers on the adjuster like to be heated up in HOT water makes them easier to go on, you'll break a few probably but YOU HAVE LOTS OF THEM. Also order a bunch of Belleville's, why you may ask, measure all of your current ones, right on the edge take an average, if you want consistency match all of the Belleville's so they all work evenly, give them a light polish and a light wipe down with the REAL OIL (synthetic). IF you don't have a digital caliper, Harbor Freight is your friend. You can actually polish up the piston and the mating surface with a leather strop, I cheat a touch a use a VERY fine lapping compound on the strop, it really doesn't take much. Keep the leather in a plastic bag when not in use, avoids contamination. Note, some of the pistons come with the Delrin sticking out about 1.5mm, that is way too high, it needs to be ALMOST flush to get enough pressure out of it. And...on the Belleville's get 100 of them, thicker means more pressure and the thicker ones are rarer on the manufacturing tolerances. Send me a PM and I can give you the numbers I've figured out, or do a search, it's posted here in a few places. Oh forgot get a good tweezer kit, it comes in handy, the ones that stay closed, Amazon.

Good Luck
Hoggie
 
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HogKiller said:
Meh, get the sizes of all of the 0-rings in the thing for the reg, go to the 0-ring Store buy a bunch, way cheaper than a dumb kit, get a good brass o-ring pick kit and a nice needle, that's for the one buried down in the hole, replace o-rings, if you don't have the new brass pistons, get them, less heart ache. If you do have the new brass pistons look at the little Delrin piece in the middle, is it concave (bad) or convex/flat (good) I'll bet on concave due to over pressure. Replace ALL of the o-rings, they're cheap because you now have LOTS of them, lube with a good oil, doesn't need to be silicon, regular synthetic won't explode in the gun. I've found that those little suckers on the adjuster like to be heated up in HOT water makes them easier to go on, you'll break a few probably but YOU HAVE LOTS OF THEM. Also order a bunch of Belleville's, why you may ask, measure all of your current ones, right on the edge take an average, if you want consistency match all of the Belleville's so they all work evenly, give them a light polish and a light wipe down with the REAL OIL (synthetic). IF you don't have a digital caliper, Harbor Freight is your friend. You can actually polish up the piston and the mating surface with a leather strop, I cheat a touch a use a VERY fine lapping compound on the strop, it really doesn't take much. Keep the leather in a plastic bag when not in use, avoids contamination. Note, some of the pistons come with the Delrin sticking out about 1.5mm, that is way too high, it needs to be ALMOST flush to get enough pressure out of it. And...on the Belleville's get 100 of them, thicker means more pressure and the thicker ones are rarer on the manufacturing tolerances. Send me a PM and I can give you the numbers I've figured out, or do a search, it's posted here in a few places. Oh forgot get a good tweezer kit, it comes in handy, the ones that stay closed, Amazon.

Good Luck
Hoggie
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If i continue to shoot with a regulator leak will it cause the reg to get damaged beyond repair?

My FX Dream tac had the same problem where the reg pressure would equalise with the tank pressure but when i dissassembled the reg the delrin piston was damaged to the point where it could not be repolished.
 
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monstr2 said:
If i continue to shoot with a regulator leak will it cause the reg to get damaged beyond repair?

My FX Dream tac had the same problem where the reg pressure would equalise with the tank pressure but when i dissassembled the reg the delrin piston was damaged to the point where it could not be repolished.
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I doubt it, you either have a bad o-ring or a bad mating surface, both are already bad so meh. THE WORSE case is you'll need a new piston for the regulator if it has a major divot in it and you can't polish it out. There really isn't much going on in the regs, only one part moves and it rubs on 3 o-rings, thusly the need for lubrication.
 
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