Shiming

[Callum861]

HI all im wondering if anyone can help me iv decided to learn to do my own tech work so I brought myself boneyard jg mp5 ras to work on to see if I could get it working and doing so iv tried shimming the gearbox myself I followed a video by the airsoft tech which iv seen a few people mention however he uses the pistol grip and half she box method which seems really easy. u

Unfortunately the gun i have i cant do that as the pistol grip and lower receiver is all one peice and so iv tried to do it and its not worked as got a awful sound. I wasnt expecting it to be right as its my first time but my question is has anyone els had the same problem with the pistol grip and lower receiver being one peice and how did you get round it when shimming it is there a different way to shim the gears when I cant use this current method? 

 

Thank you in advance 

[Mtemprell]

The way I shim up is remove everything out the gearbox and get just the 3 gears. The bevel gear have no shim on the Bottom and fit the other half of the box and test to see what play you have, then start at smallest shim and keep testing till have minimal play, you don't want it tight up otherwise it won't spin freely. For the spur fit it in with the Bevel and using a feelers gauge find the gap at the base of the gear to the bearing and use the shim that is same as that gap. Repeat again with fitting top of gear box and shimming till the play is minimal. Repeat again for the sector gear. Once done screw the gear box together with all gears and shims inside and test for correct meshing and try manually turning the gears to ensure free movement. 

 

Once your happy grease up gears and bearings and rebuild the box. It is a slow process but at the end there's big pride in what you've achieved.