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mattsa80

Gearbox jam

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Hi guys, just after some advice really as im not technically minded :)

My new cqb m4 got to the last game of the day and suddenly froze. Its not the battery or the motor as iv had that out and still turns on demand.

I freed it up once and got maybe 15 rounds out but then the same thig happened. Now as soon as i reattach it to the gearbox it cannot fire. It tries but wont go. I can turn the gearbox manually through the motor hole so it does move at least.

 

Any advice would be a great help cheers :D

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It could be that the piston Teeth have slipped and longer line up or their just Broken.

 

What type of Battery do you have and the charger for it?

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fitted with an 8.4v 1600 nunchuck in the stock

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happened to one of my guns earlier this year. Turned out that the motor height was wrong and it was jamming the gearbox. The motor connectors were buggered and pushing the motor up so it did not mesh properly with the gearbox. So out of the gun the motor worked fine and the gearbox rotated fine, put the two together and nada. Adjusted it right the way out then adjusted it back up a bit at a time and got to the point it was happily meshing.

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Cool i'll have a go with that cheers for your help. Fingers crossed :D

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Right the gearbox has lost all tension and will just turn freely anyway now :(

Im guessing this means the gearbox has to come out but its wired through the stock and i cant figure out how to get the stock off.

It is a fab defence gl-shock. Cant seem to find a video or anything about removing these, just normal crane stocks.

 

Cheers

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As I recall, and from google images, the fab defense gl-shock stocks are simply fancy crane stocks. You just need to get the stock removed (usually by forcefully pulling down on the button release you usually use to change between stock extension lengths) and then use a long screw driver to remove the buffer tube and the screw that fixes into the back of the spring guide in the gearbox.

 

And as for no gearbox tension at all? I.e. you can cycle the whole gearbox fully? That's usually very hard to do manually as the pulling of the piston with a screw driver is hard to do! If you are able to make it cycle then your piston is not engaging.

 

Plus, if it isn't your motor height causing issues, it is a gearbox jam. This can be caused by many things, but it sounds like a damaged part rather than an electrical "stalling" commonplace if you feather semi too much with a low voltage battery.

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I cant get the stock off no matter what i try and there is no screw down the tube as the wires for the battery are coming through. Its a real muddle. When i turn my gearbox through the motor hole the piston doesnt engage. It spins really easily and pull the piston at all.

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Does the buffer tube screw on? If so, then there should be nothing stopping you from removing the GB without taking the buffer tube out!

 

Some pics of how far you have disassembled it would be good!

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If the gearbox is spinning freely then your tappet plate is not engaging, so may be a bit bent.

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If the gearbox is spinning freely then your tappet plate is not engaging, so may be a bit bent.

...indeed, that too. But the main concern is the piston... however I guess the whole thing won't work if either/both are broken!

 

Now, the task is to remove the GB and then disassemble it. If you manage to do so, grab us a pic (good quality would be grand) of the internals so we can have a look to see what is broken/not working!

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