GEARS/MOTOR PROBLEM

cobra 08

Having a problem with my G&G Scar L. First the gearbox locked so brought it down to Eirsoft where they unlocked it when I got home I put a fully charged battery (practically new) in it and tried to fire it but it locked again so decided to strip it down. When I did I noticed the reverse lock was out of place so put it right and put it back together. Now when I tried to fire it again nothing:mad:. The motor is running fine on its own but as soon as it touches the gears it just stops. The gears aren't locked as they can be moved using a screwdriver with very little effort.
Any suggest/ideas would be greatly appreciated as its be out of use for nearly 6 months now:mad::mad::mad::mad::mad:
Thanks in advance...

DeBurca

I assume when you say the reverse lock that you mean the anti-reversal latch

Are you sure that you have the motor in the right way around
If you put it in 180 degrees out and connect it you are in effect running the motor in reverse and the anti-reversal latch will prevent it from turning

Check to see if there is a + stamped on the end cap of the motor or on some motors it is on the bearing support and others have the positive terminal coloured red
The + side of the motor should be facing forward towards the barrel and the - side towards the stock
Hope this helps

cobra 08

DeBurca wrote: »

I assume when you say the reverse lock that you mean the anti-reversal latch

Are you sure that you have the motor in the right way around
If you put it in 180 degrees out and connect it you are in effect running the motor in reverse and the anti-reversal latch will prevent it from turning

Check to see if there is a + stamped on the end cap of the motor or on some motors it is on the bearing support and others have the positive terminal coloured red
The + side of the motor should be facing forward towards the barrel and the - side towards the stock
Hope this helps

First thing I tried mate but thanks actually think it just might need a shim job.

DeBurca

It is rare that a G&G gearbox would be that badly shimmed that it caused a mechanically lockup, lockups are normally caused by the inability of the battery to supply the current required by the motor to overcome the resistance of the spring and so complete the rearward cycle of the piston

So if the battery is good there is the possibility that the fault lies with the motor
If the motor is stopping under load then there is a possibility that it is the motor itself that is at fault

The motor in the G&G series is there Achilles heel, I have replaced several in both GR15 Raiders and GR16 and have upgraded a Scar to a G&P M120 motor whose motor seemed to be running a tad on the slow side
Faulty motors will spin fine on their own but when subjected to a load will stop and very often have a faint smell of burnt varnish

Do you have another AEG that you could use the motor from just for a test and as a means of eliminating it before you open the gearbox ?????

cobra 08

@DeBurca too late opened gearbox turns out that the anti-reverse lock was knocked out of place ( probaly due to Bering poked at) put it back together and now seems abit stiff so going to give it a shimming and see if that helps if it that doesn't work I'll try a different motor

$kilkenny

something similar happened to an M15 i had
full battery,pullled the trigger and a little turn and nothing....
turns out the wire connecting the battery and motor was earthing off the gearbox shell...
it worked after about 5 mins with the trigger pulled but the battery would seriously overheat so dont try it
i got rid of it after so i dont no how to fix it

just check the wiring over the motor and were it enters the gearbox
thats were i found the most wear and tear

Firekitten

I bet you didnt have a fuse in that gun, or you'd have sussed wiring problem instantly... holding the trigger for 5 minutes till the battery got 'very hot' is a very silly idea ><

A quick fix for the future cobra, is know the locations of parts, so if you take it down, you can see if things are fitted correctly, and in the right locations. Test the springs in items like the anti reversal, it should hold it to the gear by default. As others said, shimming shouldnt be the problem unless the casing was overtightened. Im glad you sorted it out, working through problems yourself helps you learn how to solve them when they happen again.

josh68

i had the same problem with m4 , i also reshimed and it worked fine.
it was my first time in a gearbox but took photos as i was taken gears and springs out so i could make sure everything went back the same. good to see you got it going again

$kilkenny

Firekitten wrote: »

I bet you didnt have a fuse in that gun, or you'd have sussed wiring problem instantly... holding the trigger for 5 minutes till the battery got 'very hot' is a very silly idea ><

A quick fix for the future cobra, is know the locations of parts, so if you take it down, you can see if things are fitted correctly, and in the right locations. Test the springs in items like the anti reversal, it should hold it to the gear by default. As others said, shimming shouldnt be the problem unless the casing was overtightened. Im glad you sorted it out, working through problems yourself helps you learn how to solve them when they happen again.

no it had a fuse...
i only did it once and it was a loan gun and thats the way i got it so not my fault.
the motor gear was cutting at the wire and then it started earthing off the shell

cobra 08

Firekitten wrote: »

I bet you didnt have a fuse in that gun, or you'd have sussed wiring problem instantly... holding the trigger for 5 minutes till the battery got 'very hot' is a very silly idea ><

A quick fix for the future cobra, is know the locations of parts, so if you take it down, you can see if things are fitted correctly, and in the right locations. Test the springs in items like the anti reversal, it should hold it to the gear by default. As others said, shimming shouldnt be the problem unless the casing was overtightened. Im glad you sorted it out, working through problems yourself helps you learn how to solve them when they happen again.

Right this still is not sorted.... the gear box goes together fine shimming is perfect all wiring perfect no sign of wear anywhere but when I put the riffle back together as soon as the motor touches the gears they lock
Any suggestions?

bullets

would it be the how the Tappet plate sits on top of the
sector gear by any chance ?

Had a JLS Scar gearbox I opened and a Cyma MP5
that nearly broke my heart. The JLS scar was given to a friend in about a million pieces and told if he could put it back together he could keep it! The cyma eventually worked for me.

My issue was every time I followed a gearbox guide and thought I had everything perfectly lined up, once I closed it and put it back into the gun, I would get one shot off and the gear box would lock up again.

I noticed I had the little bit that stuck upwards from the sector gear level with the tappet place when assembling it.

The only change I made when it worked was that I placed the back of the Tappet Plate on Top of this bit so when the sector gear rotated for the first time, the bit that would engage it's starting position was physically under the tappet plate before the first rotation.


~B

glicster

just a little note on shimming that masada put me aware of when i started opening aegs. when you were doing the shim job did you tighten all the screws in the gb after shimming EACH gear? it makes a big differance to how tight the gears are rather than if you were to just hold the gb together and spin the gears.

cobra 08

Ok folks little update on this my new motor arrived ( gaurder infinate) and I put it in and still nothing? The gearbox seems fine no tension on gears or anything else I can notice so anymore ideas would be appreciated

Solid Snake

Sorry to hear that it isn't working for ya Cobra.

You're better off troubleshooting this sucker by stripping it again.

There has to be something either blocking the gears or like Glicster and Firekitten have said the gears have been overshimmed so when the gearbox is secured everything is locking up. You really need to take your time and be patient when you do this. Rushing it will just cause more problems.

Work from where the motor makes contact first - Bevel gear and work through all points of contact i.e anti reversal latch, spur gear, sector gear etc. Check and recheck. Make sure the sector gear is pulling the tappet plate backwards and that it is set properly to engage with the Piston.

Don't put a fixed time to this, if you don't get it finished in one evening then leave it and come back to it.
Best of luck with it and if it doesn't work out for ya I'm sure someone here can help.

I'll be in Redbarn this weekend so if you still can't get it working let me know and I'll have a crack at it.

Cheers

cobra 08

Cheers Solid Snake
Going to open it back now just thought someone would have a little insight into what to look for. Dont believe it's anything to do with shims spent a couple of hours on them and they spin perfect and if I reach into pistol grip the gears move very easily which is why I'm so confused. Looking back on what Bullets said I might turn my attention to the tappet plate and how it's linking with sector gear see if there is a problem there

Leftyflip

Checked the motor adjustment? It could be too tight.

cobra 08

Leftyflip wrote: »

Checked the motor adjustment? It could be too tight.

Tried adjusting both ways loosen it it grinds, tighten it it just stops.

AlternateID

cobra 08 wrote: »

Tried adjusting both ways loosen it it grinds, tighten it it just stops.

Same problem with one of my guns at the weekend. I shimmed beval gear wrong. Wasn't engaging motor correctly. Took a few attempts but working better then ever now.