FX [HELP] FX Impact M4 – Regulator Adjuster Pin Spinning Freely – Need to Replace Both Reg Parts

[brunoyui]

Hey everyone,

I could really use some help from anyone who has experience servicing the FX Impact M4.

I'm in the process of replacing both regulator components:

• The regulator adjuster pin (also called pilot or adjustment screw), and
• The regulator piston assembly (the large brass body that threads into the block).

I already have the replacement parts in hand.

The problem:​

When I insert the correct-size Allen key into the regulator adjuster pin, it just spins freely inside the block and won't back out.
It feels like the internal threads are stripped or the pin has lost bite — it keeps rotating endlessly without coming loose.

What I need to know:​

1. How do I properly remove a stuck adjuster pin that spins freely?
2. Should I remove the regulator piston body to push the pin out from behind?
3. What’s the correct method to unthread the regulator piston assembly?
   – Do I need to apply heat or is it usually dry-installed?
4. Are there any hidden risks when opening this area of the gun I should watch out for?
5. If anyone has photos or a teardown link, that would be amazing.

---

I'm comfortable with tools, but this is my first time digging into the regulator internals.

Any help would be seriously appreciated. Thanks in advance to anyone who can share tips or experience!

—Bruno

 

[Vetmx]

In your top pic the adjuster is ready to be pulled out manually. There are no threads engaged because you unscrewed it until it spun freely. Now just grab it and wiggle it out. The only thing that’s holding it are the orings. Get back to work and good luck.

 

[brunoyui]

In your top pic the adjuster is ready to be pulled out manually. There are no threads engaged because you unscrewed it until it spun freely. Now just grab it and wiggle it out. The only thing that’s holding it are the orings. Get back to work and good luck.

Thank you very much, I was afraid of pulling it and damage other things

 

[rickschowengerdt]

If you haven't yet watched some of the videos showing how to disassemble the regulator on Y. T. I would recommend that you do so. I would also recommend getting the trigger guard as well as the trigger out of the gun, so you can pull the regulator housing out hello. I hope this helps you some.

 

[Trucker3573]

Yeah was going to say most vids show pulling the trigger assembly. I would suggest watching sub12 airgunners (ok I guess there is a European channel I watch) video on the impact reg rebuild. He makes it look easy and uses a couple techniques that I think may come in handy. Ones I didn’t think of when I tore into an amp reg. I’ll be honest I found it an utter PIA to do. The video guys make it look so easy. Lol I guess I just need to get more proficient. There is a small oring in the very bottom of the regulator body. That one is a little mother —— to get back into place. Sub 12 shows a good approach and method. You get that right away you will be good.