ICS M4A1 Help.

[Renegade)]

Just got my ICS M4A1, it was working perfectly for a couple mags when I opened her up to arrange some wires in the mechbox, but something must be out of place inside the gears or piston because when I put it back together it doesnt fire the piston all the way instead just makes a grinding noise.
The gears are all in good shape and they turn with the top half of the mech box open. So any help would be very appreciated as I am scheduled to use it at FR in 2 days..

Thanks. If you need any more info at all about it, just post it and ill do my best to describe the problem more or the state of the internals.

[mcguyver]

What exactly did you do? ICS lower mechboxes are tricky beasts if you messed with the shimming at all.

[Renegade)]

All I did was pull the back pin, opened up the mechbox to arrange some wieres, didnt touch any of the gears at all at this point, when I went to close the top half it seemed like something was blocking the hatch, so I realigned the gear so the flat part of the main gear was facing up, and the top half went back perfectly, but then when I test fired it did not pull the piston back all the way and sounded like it was grinding the hell out of my insided, so I opened it up again and the piston released with the normal pop like if it had of fired, and nothing was out of place at all, the gears worked fine, lined it back up including reseting the little pin above the trigger, and it worked fine for probably 200 shots or so, and then in the middle of the bush, I took one shot then that same ear hurting grinding noise.

I got him to remove the upper half and run the mechbox to see if the grinding was comming from the lower mechbox or the upper. The lower half works fine, no grininding from the motor to the mechbox.
From what he has told me, its definatly the upper to lower mechbox meeting...must be missaligned or jammed.

[mcguyver]

Check every gear, every tooth. I have seen guys who split the receivers and hear the "pop" (bad thing) because they didn't use the forward assist to release the spring tension and actually ended up breaking teeth off a gear. It's easiest if you remove the motor so the gears will spin freely, but if you've got strong fingers, you can turn the gears by hand.

You may well have broken teeth on one of your gears. Forward assist is there for this exact reason.

The gears will spin even with broken teeth, but as soon as you apply the load of the upper, it skips at the break.

[Renegade)]

I used the forward release before I opened it up, that I knew to do.

I have it right there in front of me, and like I said, I didnt see any broken or damaged teeth really, So it has to be something misaligned in the lower, the piston seems ok, it moves freely, I think where its been grinding some of the times is the gold piston cover, it has some fresh scratches on it.

[Renegade)]

I just put it all back together properly, realigned it again, and it is firing now, but it still has a faint grind to it, hmm

[mcguyver]

That's the cylinder. Pull your upper completely out of the gun and inspect it thoroughly. Is this gun stock, or has the upper been upgraded. That cylinder should move enough to catch the sector gear.

[Renegade)]

Originally Posted by mcguyver

That's the cylinder. Pull your upper completely out of the gun and inspect it thoroughly. Is this gun stock, or has the upper been upgraded. That cylinder should move enough to catch the sector gear.

According to 27Maverick, it is stock, used once. I have the upper out and I am looking over all of it, there are scratches on the cylinder, so that could be the cause of the grinding perhaps, it does not move however, the only thing that moves in there is the black latch that moves back and forth freely. From what I can see, the upper mechbox looks fine.

[mcguyver]

I just looked at both of my uppers (1 stock and 1 Upper Kit "E") and both show 2 full teeth and full spaces for gear engagment when the piston is at rest. You should have this engagement as well.

[Renegade)]

Corect, 2 full gears, the first one is flat on the tip, and the other is a normal tooth gear. But for some reason its not engaging properly, because it starts to engage half way then grinds, and when I use the forward assist to open it back up the piston releases.

[SHaKaL]

There a little screw in the bottom of the grip... turn it clockwise a couple turn with an allen key... That's the motor adjustment screw and on my ICS M4 its alway get loose. Now i use loctite on it

[Renegade)]

Yea, I see the screw, jsut tighten it up and should be ok then? or is that just a step?

[SHaKaL]

Try it, it push the motor on the gear and what you describe happen each time mine get loose

[Renegade)]

I think u might have it shakal, I now am sure its a motor problem, its loose, and there is a small metal loose disc that fell out of the grip when I opened it, so I might have to pull the motor out right. Hmm,

sorry Brad, msn is not letting me back on now. But im trying.