Seized gears in both my AUG and M4

[Predator]

So just spent the whole afternoon over at manchovie's house trying to fix my M4 and AUG.

M4 has a reinforced gear box from G&P that came with metal body (SR16 M4). Has been shooting fine for the last 6-7 games. Upgraded with PDI 130% spring, metal bushings. It won't turn anymore, motor checks out fine, gears are fine no grinding. We narrowed it down to the spring that pulls the trigger back (the part that touches the connectors to complete the circuit). Any one have an idea of why it would happen now after all those games? And how to fix it?? Could it be the spring is too weak to pull the trigger back? If we take it apart and reseat the trigger, it doesn't happen for 5 or 6 shots. Then it happens all over again. Grrr.... we know it's partly cuz of the reinforced box, but has anyone else encountered similar problems like this? Alex/FF I know you love the G&P bodies and box so did you have something like this happening?

Secondly...

Same situation with AUG gear box, it's stock gear box, has PDI 170% wit metal bushings, guarder aluminum piston head, and G&P polycarbonate piston recently replaced in the last 3 games it's been to. Gears are seized, took it apart, reseated, reshimmed, everything and it will only fire on shot before going seized again. Could shimming too tightly be a probable cause? Or faulty G&P piston, despite the fact it's worked the last 3 games?

Argh, I'm so freakin' cursed with AEGs given recent events!

Batteries used are the same ones that the AEG used to work with. 3000mah 8.4v for M4 NIMH, and 1700mah 8.4v NICAD for AUG as well as the test 3000mah 8.4v NIMH.

Any solutions and suggestions to both problems are more than welcomed... The AUG's been fielded the least since I first bought it and I hate it having going out of commission so frequently!! So helppppp!!! :hammer: :hammer:

[mcguyver]

did you properly lube both the gears and cylinder? too much lube will cause it to be sprayed all over inside the gear box some will get on the switch contacts and cause arcing and pitting of the contacts, destroying them. not enough lube will cause a whole host of problems the least of which is gear wear and things like bushings seized to gears etc.the strength of the trigger return spring i've never found to be an issue, but i have seen excessive wear in the switch indent for the semi-auto sway bar which would cause intermittant semi operation. the selector plate should be either a g&p or marui for that m4 box as other manufacturers may not have the positioning just right for proper fire selection, but this usaully will result in semi but not full auto operation. also check the selector plate contacts with the switch and ensure that they make contact at both the semi and full auto position. a failure of even one of these contacts to engage the selector will result in a no-fire. if you have a low-resistance switch like the g&p one it doesn't have these,so disregard that test. i would do a complete teardown of both boxes and start the reassembly again and pay very special attention to shimming and lubrication. don't neglect either of these as they are the most important parts of re-assembly. it's the only way to be sure you don't miss anything. also you didn't mention whether your gears in your m4 will turn by hand with the motor out and whether you checked for proper motor positioning and engagement. this has been a problem with g&p guns and is the result of improper wiring location inside the grip with similar results to what you describe.

had the problem with my MP5k
turns out I had the wires to the motor backwards so it was pushing against the anti-reversal latch

[gandar]

Same problem with my AUG... I just finished installing a new sector gear, everything is shimmed properly, works fine without the piston in, the sector gear is set to 1 o clock when I reassemble, but it binds about half way through the cycle.

[gandar]

Ok, my shimming is good, there's no reason for it to bind, and as soon as I crack the mechbox even a smidge, the piston releases and it completes it's cycle. The diagram (shitty as it is) I included is to show where the pin on the sector gear is in it's cycle when everything locks up, and it looks like the piston has about 4-6 teeth left when it locks up. I've got no clue why this is happening, or what's causing it, PLEASE HELP! I just spent 3 hours dicking with this thing to try and get it cleared up. None of the gears are binding, and when I close the thing up with everything minus the spring, it seems to spin ok....

I believe it's a PDI 140 spring, 9.6v 1700mAh battery, standard TM gears, TOP aluminum piston (though I tried it with the stock one and the same thing happens)

[FNG]

This might be a dumb question, if so, just ignore me.

When you did the shim job. Did you screw the two halves of the mechbox together after each shim and gear you put in? Then test it. Or did you just squeeze it really hard with your fingers? I learned the hard way that this is a short cut that can't be used. I've only taken 7 mechboxes apart so I don't claim to be an expert by any means. In my opinion it's either a bad shim job or you got some wonky pistons. (I know nothing about 'wonky' pistons, so that's just speculation on my part) Good luck.

[mcguyver]

this may also sound like a dumb question, but is you sector gear in the correct way. if it is then the "nub" that strikes the tappet should be facing you. oh yeah, recheck the shimming too. everything should move freely when you turn the gears without the piston and spring in.

the anti-reveral latch could be against the gear teeth and not the slots desiginated for the anti-reveral latch.

take out the piston and spring and then run it, see if the gears will spin

[gandar]

I'll double check the anti reversal latch, it *might* be causing it, but I don't think so... Yes I did tighten everything up and check my shimming that way, it's not too tight and there's clearance everywhere. Yeah Mcguyver, I could see someone doing that, but yes my sector gear is in the right way. I'll check the anti-reversal latch when I get home tonight, actually when I first put everything in and was starting to shim, I had a similar issue in that the teeth on the sector gear that grab the pison, were binding on the teeth of the spur gear and locking it up (I was turning it by hand thankfully so I didn't just shred everything... But I have to run to class. Thanks for the input so far.