FX FX Crown regulator??

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DeanB

DeanB

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Sep 3, 2022
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Rockville, In
Bought a Crown MK2 off classifieds and just went to fill gun and noticed that reg pressure was going up with the fill, at 225 bar reg gauge read 225 bar. I shut compressor off and fired 5 shots and reg went down with pressure gauge but stayed there. When I started fill reg gauge was on 145 bar.
Does this mean reg is junk or some how stuck?
 
These regulators are frail. It does not need much to make them leak. Adjusting reg pressure will cause the sealing surfaces to abraid. One surface is plastic and the opposite surface is brass. Both are soft materials and easily damaged. jps2486 is also correct, but what he did not say is what a pain it is to change these O rings. Be very careful not to scratch the cylinder wall surfaces while picking them out.

FX has an IPB on their website that gives you the correct size and material of these O rings, O rings are perishable and you should keep on hand replacements for every O ring in use for every air gun you have. They are cheap and well worth keeping them on the shelf. Always use silicon oil on your O rings, never petroleum oil. It is also possible to re-polish these sealing surfaces, but you must use 3M polishing cloths, never sandpaper.

Also pay attention to the Belleville spring stack orientation for re-installation. Have no doubt, this is a real PITA job!
 
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steve-l said:
These regulators are frail. It does not need much to make them leak. Adjusting reg pressure will cause the sealing surfaces to abraid. One surface is plastic and the opposite surface is brass. Both are soft materials and easily damaged. jps2486 is also correct, but what he did not say is what a pain it is to change these O rings. Be very careful not to scratch the cylinder wall surfaces while picking them out.

FX has an IPB on their website that gives you the correct size and material of these O rings, O rings are perishable and you should keep on hand replacements for every O ring in use for every air gun you have. They are cheap and well worth keeping them on the shelf. Always use silicon oil on your O rings, never petroleum oil. It is also possible to re-polish these sealing surfaces, but you must use 3M polishing cloths, never sandpaper.

Also pay attention to the Belleville spring stack orientation for re-installation. Have no doubt, this is a real PITA job!
Click to expand...
Exactly what I didnt want a PITA. thanks for advice.
 
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HI,
If you are going to replace the regulator O rings may I suggest that you watch the video below. Sub12Airgunners are among the best at explaining how to do things on airguns. I also suggest investing in some "Jeweler's Glasses" to help you when working on the O ring in the receiver body.
By the way, based on your description of the problem it doesn't necessarily have to be the O rings. Watch the video and he tells you where the air will leak for each O ring failure. Your problem might be the regulator piston. If you have an older rifle it will be made of delrin. The newer ones have a brass piston with a delrin cap. If the mating surfaces are worn or gouged, then the regulator will not function. That sounds like your problem. By the way a whole new regulator isn't all that expensive (relative to how expensive the rifles are).
Cheers,
Greg


Here is the regulator video. It shows work on an Impact, but the regulators are the same as in the Crown MkII and late MK 1's. If you have an early Mk I Crown you will have a smaller diameter regulator. Utah Airguns can tell by your serial number what parts you need.

This is the Jeweler's Glasses I bought. I found them very useful.
 
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NAProf said:
HI,
If you are going to replace the regulator O rings may I suggest that you watch the video below. Sub12Airgunners are among the best at explaining how to do things on airguns. I also suggest investing in some "Jeweler's Glasses" to help you when working on the O ring in the receiver body.
By the way, based on your description of the problem it doesn't necessarily have to be the O rings. Watch the video and he tells you where the air will leak for each O ring failure. Your problem might be the regulator piston. If you have an older rifle it will be made of delrin. The newer ones have a brass piston with a delrin cap. If the mating surfaces are worn or gouged, then the regulator will not function. That sounds like your problem. By the way a whole new regulator isn't all that expensive (relative to how expensive the rifles are).
Cheers,
Greg


Here is the regulator video. It shows work on an Impact, but the regulators are the same as in the Crown MkII and late MK 1's. If you have an early Mk I Crown you will have a smaller diameter regulator. Utah Airguns can tell by your serial number what parts you need.

This is the Jeweler's Glasses I bought. I found them very useful.
Click to expand...
Previous owner said it has brass piston reg. Im not really sure I want to work on it as I dont really have the extra tools needed for reg removal etc and if going to mess with might as well get a complete reseal done.
 
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jps2486 said:
The alternatives are to 1. Send the gun out for repair, or 2. Buy a new regulator for $120. Personally, a dollars worth of O rings is a good choice for me.
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Well if those o rings are failing then more then likely the rest of them are in same condition or close. Id rather have a complete reseal done then at least have peace of mind that its not going to mess up when I least want it to.
 
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Patrick1 said:
Don't forget to "maintain" the o-rings
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Just did lube job on my Two.
Mind you not every O-ring even if it have less than any FX i am aware of, but just the heart, so valve and immediate surroundings and regulator.

Took me about 30 minutes to do, pressured back up to the 240 BAR i had, and put away with reg pressure of 61 BAR, and pressures was the same 30 hours later.
 
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DeanB said:
If some o rings are dried out going bad do you not think that more then likely others could be in same condition.
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Possibly, but O-rings in a regulator tend to degrade more rapidly than elsewhere in the pressurized system, particularly those on the high pressure side. Meaning those toward the narrow end of the piston. Why is that? Because of thermal stress of the refill cycle. Heat essentially cooks the elastomer and it becomes hard and brittle over time.

This embrittlement is the most common form of “drying out” that occurs. However there is also a slower form caused by oxidation. Lubricating seals with silicone grease slows this effect to some degree by reducing the rate of gas diffusion through the material.
 
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The Crown reg is a good one, even the delrin piston isn't all that bad, it's more perception. Any reg with a brass piston has a delrin sealing surface, so that is usually a non issue in and of itself. The problem with any reg is adjusting it up while under pressure, ..that will damage it asap.
I have probably five or six regs for my MK2, a delrin factory reg, a brass factory reg and three or four Huma regs with various spring stacks. Of all of them, I like the Huma with the low pressure stack which is adjustable from 60-135 bar. It seems to give very good results. I have an old style Huma Medium pressure stack that also does well, and I can't remember it's range. I have yet to try the new, latest factory reg, as I'm pretty happy where I'm at for now.

When my MK2 arrived it had a delrin piston and worked very well, the Huma is only a tiny bit better.
 
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bchannell said:
The Crown reg is a good one, even the delrin piston isn't all that bad, it's more perception. Any reg with a brass piston has a delrin sealing surface, so that is usually a non issue in and of itself. The problem with any reg is adjusting it up while under pressure, ..that will damage it asap.
I have probably five or six regs for my MK2, a delrin factory reg, a brass factory reg and three or four Huma regs with various spring stacks. Of all of them, I like the Huma with the low pressure stack which is adjustable from 60-135 bar. It seems to give very good results. I have an old style Huma Medium pressure stack that also does well, and I can't remember it's range. I have yet to try the new, latest factory reg, as I'm pretty happy where I'm at for now.

When my MK2 arrived it had a delrin piston and worked very well, the Huma is only a tiny bit better.
Click to expand...
No insult intended
And no desire to be hyper critical
But for some reason I recall reading the opposite
That lowering the regulator under pressure is the no-no
Do I have it backwards?

Edward
 
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SilentSquirrel said:
No insult intended
And no desire to be hyper critical
But for some reason I recall reading the opposite
That lowering the regulator under pressure is the no-no
Do I have it backwards?

Edward
Click to expand...
Nope, you got me there, good catch. I meant to say when you're adjusting DOWN under pressure. My mistake.
 
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