Image 1/2: If the AEG is wired to the rear then it should look like it does in the first picture. Image 2/2: Check to see if the switch spring is attached to the post on the gearbox and the trigger plunger.
  • The first step to re-assembling the gearbox is to make sure the wiring is in the right place. Check the switch itself is in position and screwed down.

  • If the AEG is wired to the rear then it should look like it does in the first picture.

  • Check to see if the switch spring is attached to the post on the gearbox and the trigger plunger.

  • Make sure the red wire going across the area circled is on the bottom.

  • Warning: If the wire going across is on the top it will make contact with the motor's gear stripping the wire and creating a electrical short.

  • Now you can add the trigger make sure the spring that fits on the trigger is attached. Without that spring the trigger will not be able to reset after a shot on semi-auto.

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Image 1/2: Once again try not to lose the shim placement on the gears. Image 2/2: The first gear to place back in the gearbox is  the spur gear (the large round gear)
  • Now the gears can be placed in the gearbox.

  • Once again try not to lose the shim placement on the gears.

  • The first gear to place back in the gearbox is the spur gear (the large round gear)

  • Next comes the Sector gear which has a half set of teeth and place it with the post shown in the 2 O'clock position

  • Next grab the anti-reversal latch and spring and fit them together with the loop of the spring going on the long post and hook section on on arm part. Then place them in the hole shown.

  • Keep The anti-reversal latch poled back so that you can place the bevel gear in position. The Bevel Gear is the on with the G&G logo on it.

  • Make sure the anti-reversal latch and trigger will not pop out of position by adjusting how the spring pushes against the gearbox wall.

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Image 1/1: Now take the cylinder out so you can add parts to it.
  • Now take the cylinder set the cylinder head in side if it isn't already. The placement should be such that the two parts fit flush with indentations in the gearbox. This done to check if this is the case before you put the other parts on the cylinder.

  • Now take the cylinder out so you can add parts to it.

  • Then slide the air-nozzle on to the cylinder head and slide tappet plate onto the air-nozzle.

  • You can now put cylinder and all the parts attached into the gearbox as shown.

  • Now put the piston in the cylinder. Make sure the piston tacks aligned properly with the track of the gearbox and the teeth of the piston are facing the gears.

  • Finally take the tappet-spring and attach it to the tappet plate hook and the gearbox post shown. Without this spring the gun will not be able to load BB's.

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Image 1/1: Make sure to hold the piston down as shown wile working further.
  • Now you can add the spring and spring-guide.

  • Make sure to hold the piston down as shown wile working further.

  • Now make sure that all of the parts are not out of alignment or set in a way that would stop the gearbox shell from meeting.

  • The most common offenders are the safety latch, the anti-reversal latch, the rear wiring and the piston.

  • You can now take a long thin screw driver and slide it threw the hallow spring guide to hold down the piston and take the other half of the gearbox shell and line it up first with the front of the gearbox and begin pressing it in place.

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Image 1/2: Use your small thin tools to re-position problem parts if possible. Image 2/2: First with the gearbox held together by hand, check for proper wire and safety-latch placement.
  • If you somehow managed to get everything aligned perfect great, but 9 times out of ten this will not be the case. If so fallowing will allow you to line up problem parts hopefully without re-opening the gearbox.

  • Use your small thin tools to re-position problem parts if possible.

  • First with the gearbox held together by hand, check for proper wire and safety-latch placement.

  • Then try to make sure you have the spring guide in place. If so then you can keep holding the two haves together.

  • At this point check to see if the gear and anti reversal-latch axles are placed in the bearing, if not you can manipulate the position of these parts with a small thin tool. If the anti-reversal latch is too far out of position you might have to take the gearbox apart again and retry step 3 and 4.

  • If all the parts covered so far look like they are in position but the gearbox is still slightly cracked open it is most likely the piston. Luckily there is a trick to dealing with this. Which will be step 6.

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  • Wile holding the gearbox together take a long driver that fits down the cylinder head preferably with a flat bottom ( a 2.5mm hex driver is perfect) and push the piston back. The piston will most likely snap right into place.

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Image 1/1: Once that's done you can begin going threw and checking a few parts to be sure everything is done correctly.
  • After that you should have everything in place and can begin adding the screws to the gearbox. The best idea is to start with the center screw and work your way outward.

  • Once that's done you can begin going threw and checking a few parts to be sure everything is done correctly.

  • First check the piston by repeating step 6. This done for a few reasons

  • First to make sure the piston is properly in place because that doesn't always prevent the gearbox from fitting together

  • Second if you are using a piston from a different manufacturer some brand can be way to fat and will be dragging on the sides of the gearbox when moving back and forth. This will cause low velocity and catastrophic failure of both the piston and over time the gears.

  • Now Check the air-nozzle and tappet plate by gently grabbing the air-nozzle by pushing it easily back and letting go. It should spring back into position quickly and smoothly.

  • If it does not function properly do not force it as this could damage parts. This could be a result of improper installation or a bad fit if you are using a non-G&G air-nozzle and or tappet plate.

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Image 1/3: So first put the small green rubber gasket piece in place as shown. Have the side that is more rounded facing up and flatter side facing down. Image 2/3: Now take the blow back cylinder piece shown in the second picture and press it in place on top of the gearbox. Image 3/3: Now take the blow back cylinder piece shown in the second picture and press it in place on top of the gearbox.
  • Now that the gearbox is altogether it is now time rebuild the blow-back assemble.

  • So first put the small green rubber gasket piece in place as shown. Have the side that is more rounded facing up and flatter side facing down.

  • Now take the blow back cylinder piece shown in the second picture and press it in place on top of the gearbox.

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Image 1/1: Next you can add the gearbox retainer strap to the rear top section of the gearbox.
  • With blow back cylinder in position you can now add the black cylinder retainer piece. Just line it and slide on as shown. It helps to have a soft mallet if you are having difficulty.

  • Next you can add the gearbox retainer strap to the rear top section of the gearbox.

  • Have the larger hole at the back so you will have a easier time removing it for future gearbox maintenance or modification.

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Image 1/2: Image 2/2:
  • Now careful take the fake bolt and line the two hooking sections with the slightly larger opening on the cylinder retainer piece. If they are lined up properly you should be able to push the hooking sections into the place with a slight snap to them.

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Image 1/2: Now you can add a C-clip to secure the fake bolt to the piston of the blowback system. Image 2/2: You can add the C-clip can be added by holding it into position and press into place with pliers
  • You can now slide the fake bolt forward and fit the hole in the back of the fake bolt over the piston piece.

  • Now you can add a C-clip to secure the fake bolt to the piston of the blowback system.

  • You can add the C-clip can be added by holding it into position and press into place with pliers

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Image 1/2: Take the side with the long arm and with the axle attached slide it in the position shown. Image 2/2: On the other side press the gear part on to the linking axle piece and have the gear line up with the selector as shown.
  • Now you can install the selector link piece.

  • Take the side with the long arm and with the axle attached slide it in the position shown.

  • On the other side press the gear part on to the linking axle piece and have the gear line up with the selector as shown.

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Image 1/3: Set the indicator pointing up word aka the semi-auto position. Although it will most likely move out of place wile placing the gearbox in the lower. Image 2/3: Next make sure the piece that hold the fake bolt back is in the position shown. Image 3/3: Next make sure the piece that hold the fake bolt back is in the position shown.
  • Now before placing the gearbox in the AEG lower body make sure the selector indicator is placed in the gearbox.

  • Set the indicator pointing up word aka the semi-auto position. Although it will most likely move out of place wile placing the gearbox in the lower.

  • Next make sure the piece that hold the fake bolt back is in the position shown.

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Image 1/2: First set the selector to safe and and start positioning the gearbox in the body, Make sure the rear wiring is sticking out the back hole. And the motor wiring is coming out of the bottom area. Image 2/2: As the gearbox is almost all the way in change the selector to semi to both help gearbox get into position and allow the selector indicator to match the selector itself.
  • Now we can have final get to putting the gearbox back where it belongs.

  • First set the selector to safe and and start positioning the gearbox in the body, Make sure the rear wiring is sticking out the back hole. And the motor wiring is coming out of the bottom area.

  • As the gearbox is almost all the way in change the selector to semi to both help gearbox get into position and allow the selector indicator to match the selector itself.

  • If the Indicator does not match the selector push the gearbox slightly out so the indicator piece is not making contact and using your finger turn indicator into the same position as the selector and then let the gearbox down again. This may take a few tries to get it right.

  • Once the indicator and selector are aligned and the gearbox is set into position set the gun to safe and see if the indicator fallow selector correctly.

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Image 1/1: To make it easier you can push in the large body pin at the rear first but if you find it difficult to get the small pin  lined up correctly try doing it with large pin in the outward position.
  • Using a punch and or a soft mallet push the small body pin into place. Remember the textured side goes in last

  • To make it easier you can push in the large body pin at the rear first but if you find it difficult to get the small pin lined up correctly try doing it with large pin in the outward position.

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Image 1/3: Make sure the wiring is going threw the two medium sized holes. With red wire coming out of the front hole and  the black wire coming out of the rear hole. Image 2/3: Make sure that none of the wiring is caught between the bottom of the gearbox and inner top section of the pistol grip. Image 3/3: Now add the grip screws which are black with wide round head. There are only two of them despite having 4 screw holes.  Just make sure the screws are diagonal to each other like  in first picture and then screw them down tightly and evenly.
  • Now you can add the pistol grip to the gearbox of the gun.

  • Make sure the wiring is going threw the two medium sized holes. With red wire coming out of the front hole and the black wire coming out of the rear hole.

  • Make sure that none of the wiring is caught between the bottom of the gearbox and inner top section of the pistol grip.

  • Now add the grip screws which are black with wide round head. There are only two of them despite having 4 screw holes. Just make sure the screws are diagonal to each other like in first picture and then screw them down tightly and evenly.

  • You may find it easier to add the screws to the grip before sliding it on the gearbox.

  • Now crease red wire as shown in the second picture so that the wire will be coming up from the back of the grip. Forgetting to add this crease is a really common mistake.

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Image 1/3: Look for the positive symbol on the top of the motor. This represents the positive connector tab right next to it and should be  facing the front of the gun as shown, when it is placed into the grip. Image 2/3: With the wiring tucked in back of grip slide the motor in. If installed correctly the motor should move up and down smoothing and bounce when the motor is pushed down and then released. Image 3/3: You can now connect the wiring to the motor first start with the negative/black connector then the positive/red connector. The red goes with the positive symbol.
  • Now the motor can be added to the pistol grip. Make sure the spring is attacked to the front of the motor.

  • Look for the positive symbol on the top of the motor. This represents the positive connector tab right next to it and should be facing the front of the gun as shown, when it is placed into the grip.

  • With the wiring tucked in back of grip slide the motor in. If installed correctly the motor should move up and down smoothing and bounce when the motor is pushed down and then released.

  • You can now connect the wiring to the motor first start with the negative/black connector then the positive/red connector. The red goes with the positive symbol.

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Image 1/1: Avoid pinching wires.
  • Now the motor plate can be added to the end of the pistol grip.

  • Avoid pinching wires.

  • With the plate pressed in place take the motor plate screws (which are 2mm hex with cone style head) and screw the plate down.

  • It is not a bad idea to screw both screw a little loose at first and then finish tightening them after both are in place.

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Image 1/3: If that is the case you can add the magazine catch. Image 2/3: Take the magazine release button and spring. Begin pressing it into the receiver. Image 3/3: Take magazine catch piece and put it threw the other side and  start turning it counter-clockwise to thread the two pieces together.
  • Now you can add the rear wiring and test cycle the gearbox to see if you did everything correctly.

  • If that is the case you can add the magazine catch.

  • Take the magazine release button and spring. Begin pressing it into the receiver.

  • Take magazine catch piece and put it threw the other side and start turning it counter-clockwise to thread the two pieces together.

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Image 1/1: It connects to a little arm that can be seen behind the gearbox and is held in to the body by a very small pin with a little retention O-ring on it.
  • Magazine catch in place add the bolt catch.

  • It connects to a little arm that can be seen behind the gearbox and is held in to the body by a very small pin with a little retention O-ring on it.

  • Simply find that pin and push it into place when the punch is pointing.

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Image 1/3: Start with the sling adapter. The protruding section go into the AEG and the wiring goes threw the middle. Image 2/3: Then with the wiring going threw the in slide the buffer-tube on to the back page of the body. Image 3/3: Then grab the large bolt with the washer piece attached and slide them into the back of the buffer-tube with the wring set underneath. Once the bolt is as far as it will go start screwing down the bolt using a long Philips screw driver.
  • Now you can add the sling adapter and buffer-tube to the back of the AEG.

  • Start with the sling adapter. The protruding section go into the AEG and the wiring goes threw the middle.

  • Then with the wiring going threw the in slide the buffer-tube on to the back page of the body.

  • Then grab the large bolt with the washer piece attached and slide them into the back of the buffer-tube with the wring set underneath. Once the bolt is as far as it will go start screwing down the bolt using a long Philips screw driver.

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Image 1/2: Take the hook on the spring shown and attach it to the little hoops on the from of the blow-back assemble. Image 2/2: Then take the hook on the charging handle and attack it to the hoop on the spring. Then set the Charging handle in place so that it can pole back the fake and rest on top of the blow-back assemble.
  • Now you can add the charging handle and spring to the top of the gear box.

  • Take the hook on the spring shown and attach it to the little hoops on the from of the blow-back assemble.

  • Then take the hook on the charging handle and attack it to the hoop on the spring. Then set the Charging handle in place so that it can pole back the fake and rest on top of the blow-back assemble.

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Image 1/3: Try to keep the two receivers flush together and make sure the dust cover does not get in the way. Image 2/3: Try to keep the two receivers flush together and make sure the dust cover does not get in the way. Image 3/3: Try to keep the two receivers flush together and make sure the dust cover does not get in the way.
  • With the hop up all the way in the upper receiver you can slide the upper and lower together.

  • Try to keep the two receivers flush together and make sure the dust cover does not get in the way.

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Image 1/3: Try to keep the two receivers flush together and make sure the dust cover does not get in the way. Image 2/3: Once the two half's are together press in the forward body pin to lock everything in place. Image 3/3: Once the two half's are together press in the forward body pin to lock everything in place.
  • With the hop-up unit all the way in the upper receiver you can slide the upper and lower together.

  • Try to keep the two receivers flush together and make sure the dust cover does not get in the way.

  • Once the two half's are together press in the forward body pin to lock everything in place.

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Image 1/3: Pole back the delt ring as shown. Image 2/3: Place the upper rail on first and the lower piece. Image 3/3: Final screw down the screw located on the top to secure everything in place.
  • If the rails where removed front. Now is a good time to put them back on.

  • Pole back the delt ring as shown.

  • Place the upper rail on first and the lower piece.

  • Final screw down the screw located on the top to secure everything in place.

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Image 1/3: To do this pull down word on the stock adjustment leaver. Image 2/3: Now you can add the remaining stock pieces as well as your battery and test fire the gun. Image 3/3: Have fun!
  • Now without pinching the wires coming out of the back of the buffer-tube slide the stock back on.

  • To do this pull down word on the stock adjustment leaver.

  • Now you can add the remaining stock pieces as well as your battery and test fire the gun.

  • Have fun!

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Conclusion

To reassemble your device, follow these instructions in reverse order.

One other person completed this guide.

101 Tech USA

Member since: 08/06/2012

2,920 Reputation

17 Guides authored

One Comment

Do you know where I can buy c-clips? I own a GR16 and noticed that the fake bolt doesn't want to stay with the piston. It might have been because I had a friend of mine install a new spring for me and he might have taken off the clip and forgot to put it back on. You wouldn't happen to know where I can buy a new one, would you?

Degree23 - Reply

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