G3 Breakdown Guide
Written by ASF.KrYpTiK



Suggested Tools:

Phillips head screwdriver
Standard head screwdriver
Tweezers (if handling hopup sleeve)
Silicone lubricant (if handling hopup)
Mini Screwdriver Set

The G3 is a fairly simple gun to breakdown: that is one of the reasons I chose to add it to my collection. By following this guide, you will become as proficient as I in disassembling this beast of a gun. This guide pertains to all G3 variant receivers, including the MC-51, G3 SAS, G3 SG/1, both CA SAR models, CA HK33E, and more. Although this is a TM SG/1 which has been highly modified, all of the elements of a standard G3 are still there. Now, for the guide:


First, we start by removing the two screws as seen above. Use a standard flathead screwdriver to unscrew both pins holding the stock together. There are two parts of the pin, the main body of the pin and the screw on pin heads, make sure to not loose either.



Once the pins are out of the receiver and stock, pull the stock and stock cap from the receiver. The picture above shows the stock removed from the receiver. Remember, those are deans connectors, you will have clear plastic tamiya connectors. I will be writing a deans ultra connector installation guide soon.



The next pin that has to be removed is the magazine well receiver pin. This is what holds the two halves of the receivers together. Use a flathead to unscrew both sides of this pin and remove it.




Once the pin is removed pull the lower receiver (pictured as the top receiver) towards the rear of the gun and out. It should be a clean slide, with no obstructions. Make sure to not loose the golden magazine catch cylinder, which is prone to falling out.



Here are the two receiver halves split, the lower receiver is on top, the upper receiver is show on the bottom.

Now: This portion of the guide will show how to get to the hopup unit. If you just need to get to the gearbox, skip this portion.



Inside the upper receiver is the hopup, which is connected to the inner barrel. Just put your finger into the magazine well, and push the hopup chamber towards the rear of the gun, and pull it with the inner barrel.



Pull the hop-up adjustment dial from the hopup unit.




Remove the plastic hopup clip that attaches the hopup to the inner barrel.



Once the clip is off, pull the barrel out while turning it, with the hopup sleeve. Under the plastic lever on top should be the hopup bucking.

NEXT: This is the lower receiver removal portion of this guide.



When we left off, we had this, the lower receiver with the gearbox still attached.


The screw that secures the alignment assembly to the gearbox must be removed by using a standard Phillips head screwdriver.





The selector switch must now be removed. Use a mini screwdriver, the smallest one in the set, to remove the screw. DO NOT LOOSE THIS SCREW! When you have removed the screw and selector switch, make sure to put the screw back onto the selector switch, while its out of the lower receiver, to avoid loosing it or misplacing it. Also remove the right side selector dial once the switch has been removed.



Next, we have to remove the motor plate, at the bottom of the handgrip. The hex screw in the middle is the motor adjustment screw, and does not have to be touched now. Only the two Phillips head screws must be removed.



This is the two Phillips screws removed, and the motor plate removed. Be wary of the motor adjustment plate, which is the small washer seen to the left of the motor plate.



Next, remove the motor by disconnecting the two leads, and pulling the motor out. This is the picture of the motor removed.




Next, we need to remove the handgrip from the lower receiver and gearbox. Remove the two magnetic screws at the bottom of the handgrip. A magnetic screwdriver is preferred, just incase one falls out, you can easily reset it.



Once the two screws have been completely unscrewed, just pull the handgrip diagonally off the receiver. When you put the motor grip back on, make sure the wires and screws go into the correct holes. The middle hole, which is the largest, is for the motor pinion gear and axle.



Finally, after all of the above steps have been completed, pull the lower receiver off of the mechbox. It should be an easy slide!



These are some pictures of the version 2 mechbox at gearbox level.


[img]http://img204.imageshack.us/img204/21/guides31and326ge.th.jpg[/img]

This is the internal selector switch bracket. This small plastic piece is what moves the selector plate when the selector switch is moved to a different selection. Make sure you do not loose this, and put it in the right way. It should be put on the left side of the receiver.

[img]http://img158.imageshack.us/img158/6813/guides0347jk.th.jpg[/img]

This is how the motor should be put back into the handgrip, when you are done. Make sure the red positive lead matches with the red positive terminal. There should be a reference, like red paint, or a plus, like on my Systema motor. The circular, raised part of the motor (highlighted in blue/purple) is where the motor adjustment washer should be placed when sealing the handgrip.

Once you are ready to put the gun back together, follow the steps in reverse order. Thank you for taking the time to read this guide. If this is posted or quoted on a different forum or website, please post my nickname, KrYpTiK, as to give me credit, which would be greatly appreciated.

My contact information:

Email = CsS_MarrsoollPLEASE DO NOT POST EMAIL ADDRESSES IN YOUR MESSAGES - USE THE PM SYSTEM / UNLESS OF COURSE YOU LIKE SIGNING UP FOR A YEAR SUPPLY OF SPAMhotmail.com
AIM = mattbez22
MSN Messenger = CsS_MarrsoollPLEASE DO NOT POST EMAIL ADDRESSES IN YOUR MESSAGES - USE THE PM SYSTEM / UNLESS OF COURSE YOU LIKE SIGNING UP FOR A YEAR SUPPLY OF SPAMhotmail.com

-ASF.KrYpTiK


Thanks once again for viewing. This is one of a series of guides I am going to make this summer. Feel free to bookmark it for later use.

I know from taking my SG1 apart down to every last screw; this guide is everything you should and need to know.

that was a lot of help. I'll be using this.

Thank YOu this is so helpful. I really didnt know what to start with and this answered all my questions.

thanks to you, I managed to successfully access my gearbox and hop up! THANKS!

Now I have the Pulse R 72 and it is that same body as This gun and I was wonder if this is that same way you take apart the Pulse.

Nice guide. BTW you have a very nice house..well garden.

This is amazingly perfect for what I am about to do. Thanks a lot, man.

What is that brass ring in the pic of the hop up?

for somereason I was firing myjgg3 sg1 and it just stoppedshooting. I don't know why and im pissed off cause I got it 3 days agoo, the battery was half charge too! dammit I don't know what happened

will this work for my g3a3??

I would assume so... since it works with the SG-1 too.

Okay cool

Probably not, arn't all the Pulse guns LPEGs?

And yes, this guide would work for a G3A3, as Kryptic said, "both SAR models." CA calls their G3A3 the SAR Sportmatch.

Thanks for this guide, I was having so much problems with the selector plate bracket!

This post has been edited by Lizzard: Aug 15 2008, 10:17 AM

Do G3s have a version 2 or 3 gearbox? I thought it was ver. 3, but the review says 2.

G3s use V2 GBs.

where do I put the brass ring when im reassembling hopup

HELP!!!!!!!!!!!!!!!! I bought a Echo1 G3 SG1 DSR took the gear box apart and put it together with no problems but I think I put the Anti- reverse latch in wrong does any one have photos on how its supposed to be put in please!!!!!!!!

Fixed it!!!!!!!!

Edit your post. We don't need the second post in here, you could just edit the original and say:

EDIT: I fixed the problem.

You also don't need 108923723987 exclamation points after each sentence.

where do I put the little ring when assembling hopup

what scope rail and suppressor is he using? can anyone tell me everything he added to the outside of the gun?

This post has been edited by REVORACER: Nov 12 2008, 07:11 AM

Send him a PM, you'll get a quicker and better response that way.

I'm having a similar (possibly the same) problem. I've had my jg g3 for about 4 months now, I've put maybe 1,500-2,000 rounds, at most, through it. it worked fine, but yesterday I took it out for some target practice (first time I've used it in about a month) and it's not working. there's no juice getting to the motor. the battery's working because I tried it on one of my lpegs and it worked fine. I took it apart to see if I could see anything wrong with the wires, and nothing seemed like it was messed up, so if it is in the wires, it's probably an internal problem (as in, inside the rubber jacket of the wire). I also put a new fuse in it, still nothing.

just to describe the problem a little better: I pull the trigger, and it's the same thing that happens when there's no battery in the gun. the trigger goes back, but nothing happens. no electricity seems to be getting to the motor (that's a guess, I'm not an electrician).

so does anyone know what the problem might be? I'll probably be taking the trigger apart soon, to see if that's the problem, if it isn't that, my guess is that it's a motor or wiring thing.

Could be the motor, or another electrical problem, not necessarily the wires.

I had the exact same problem with my G3 today. its a JG as well. it had been working fine and we had just finished our first game of the morning. I was taking some shots into a sand bank and it stopped shooting (I was in semi), it would shoot every 10 trigger pulls or so, but auto didnt work at all. and now the gun is totally out of commission.

The working on and off thing led me to believe the problem was electrical, but my fuse is in tact and I tested the battery in my friends AK. it held steady for an entire match. I would appreciate any input you guys have about this, because id really like to fix my gun.

This belongs in AEG's or Upgrades, but it's all good. It's probably a wiring or selector switch issue. When you fire the gun and hear the sound of the motor but no gears spinning or BB's firing, two common problems are the battery and the poles on the motor. If there isn't enough power to turn the motor because the batter is low, the motor will strain against the spring, but will be unable to turn pull the piston back. The second problem, reversal of the poles, is common with V2 gearboxes because when plugging the wires into the motor contacts, it's easy to accidentally switch your red and black. This causes the motor to spin in the opposite direction. Fortunately, that's where the anti-reversal latch comes in handy, preventing gears from going backwards and all kinds of :pain: and limbo from occurring within the gearbox. If switching the wires doesn't work and the battery is plenty amped, then the problem likely lies in selector assembly, which is a topic to be covered by one more experienced than myself.

TO WHOMEVER'S G3 STOPPED WORKING AFTER SHOOTING IN SEMI-AUTOMATIC:

Your trigger post broke. Since the mechbox shells on the JG G3s are made from ubercheap potmetal, it's an extremely common problem.

It's a retardedly simple piece to break, but the options you have aren't all that great:

~Remove the cutoff lever, disabling semi-auto. Since the trigger contact block won't be getting pushed out of the way and springing back after a shot on semi-auto, you won't need the post.

~Replace the gearbox shell, for a rather undesirable sum of money.

~Drill a hole where the post used to be (often indicated by a lightish square behind the trigger contacts) and replace it with a roll pin or something.

This post has been edited by Murph9935: Aug 30 2009, 03:17 PM