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Tuning Another M3 Leak Thread

My M3 leaks and I'd like to systematically ID the source and fix it. I've seen Earnest's video on common sources for leaks on an Impact, but wondering if there's anything different for the M3 and more procedural. For example, last night I pulled the bottle and depressurized everything before the 2nd reg. As of this AM it's still at full pressure. In general I was expecting either full or empty as a small leak would have opened the regulator and quickly bled the whole thing. So, seems reasonable to assume the leak is before the 2nd reg. Where are the primary suspects and best way to test them? Are there ways to take other parts of the system out of the equation to help zero in on the source? You guys use an aerosol leak detector or soapy water? Thanks for the support.
 
Don't know if it was drilled too deep or another machining process cut into it. Either way FX is trying to fix it with a sealant which, in my opinion, is not acceptable on a $2300 gun.

Still I figure FX has their reasons for doing so so the point is a mute one. I expect they have already reprogrammed their CNC machines to not do this by now though.
 
Yes, is a true statement but from what I have personally witnessed FX stands by their guns when it comes to warranty. So if later on down the road someone has a problem because of this the warranty will still be in effect.

My Gen1 gun had a rear block problem a month or two back. At three plus years old the warranty should have been up. FX said it was a defect on some guns and warrantied the block anyway and one of the barrel inlets it damaged as well. So, they saved me $200 even when they could have let it pass and made money on the deal.

So, I have a little bit of faith they will do the right thing when this problem comes up some years down the line.
 
The M3s have a new leak problem caused by the way FX machined the trigger block. I believe it is one of the front screws that holds the trigger guard on. I would check that, the first reg and bottle gauges and the bottle fitting.

Some people use the leak detector others soapy water. Either one will werq just fine.

Checked these areas with soapy H2O, but didn't find anything. What's between the 1st and 2nd reg? Seems like maybe it's there. Will recheck everything too, but I was hoping to get lucky. Thanks.
 
Mine was leaking from the trigger guard screw. Sent it back for repair six weeks ago and I've been told they're waiting for parts in order to fix it. Hopefully I get it back in a few weeks. I'd like to dial it back in and reduce the squirrel population around here before fall arrives.

Which one? I checked mine with the guard on and pulled the guard and tested the threaded holes, nothing. Will need to check everything again, maybe I missed it.
 
The trigger guard hole issue has been fixed, it was on some of the early M3's. If yours has that issue you will see two small grub screws in the front trigger guard screw holes (3x3 mm).

Other than that, check the bottle connector/first regulator (small weep hole at bottom of the connector), the bottle connector and bottle, the brass plugs D95 (behind and partially hidden by the bottle connector) and D95.1 on the schematic, Both gauges (bottle and the first regulator) where they screw in as well as the gauges themselves, screws D68 and D91 on the schematic and the fill connection.



https://fxairguns.com/wp-content/uploads/2021/04/F10370-Impact-M3-1.pdf
 
No luck with checking the target areas recommend by FX. I'm down about 20 bar over the last 24 hours. I do in fact have grub screws in the front trigger guard holes. However I didn't see any signs of a leak from them. I'm not sure what is the best way to check the actual gauges. Beyond that I'm pretty sure about everything suggested. Thanks.


I understand your frustration. It took me awhile to nail down the source of my leak. Ironically enough if I would have spent the time reading the forums I would have come across the info regarding my issue. I went as far as to seal my bottle in a large freezer bag for a day to check for leaks. I tried the balloon over the muzzle just in case it was leaking from the valve. You name it, I tried it. In the end my problem was caused by a previously unforeseen manufacturing error. Hopefully you get everything sorted out soon. When you find where it's leaking please keep us updated as it may help someone else in the future. 
 
Tried something, probably not novel, but sealed up the "flat" areas with Scotch tape and see if anything blows off. Anyway, I could immediately feel a bubble at screw D68. So, I simply tightened it a bit and it seemed to stop. Question, is this the source of the leak or simply where it can be detected? There's no o-ring here on the schematic, so I'm wondering if this is meant to hold pressure. I won't dig deeper if I don't have to, but it this is just the symptom of a different problem I'd like to know. Hope that's clear and thanks again for the troubleshooting pointers.
 
Thanks again to all who helped out with this leak. Good news, after tightening, holds pressure great. However after some time of time away I pulled this gun out and power seemed down, so I grabbed the chrono to confirm. Here's where my tune was...

Screen Shot 2021-08-02 at 7.32.17 PM.1627950892.png


Now here are the FPS at three micro adjuster settings firing 18.1 gr JSBs.

2.0 = 695, 2.5 = 810, 3.0 = 889

Any chance tightening D68 is connected to this observation? Other ideas? Seems like such strange drop in power without changing any settings. Much appreciated.