First Time Teching, Observations Etc.

[Ebeneezer Goode]

Had the UAR apart (again) today to solve a niggly ongoing FPS/hop issue which I (correctly) suspected was an air leak. While I was at it I decided to check the cylinder air seal and the general condition of the gearbox, seeing as I've had the gun a couple of years now. As its my first time inside an AEG's guts I thought I'd share my thoughts...

Armed with Poundland's finest Rolson mini screwdrivers and a YT video explaining V3 gearbox disassembly/reassembly, I cracked on.

Disassembly was a piece of cake. Motor removed via two screws, remove the selector levers, three (or was it four? Cannae remember) hold the shell together plus (on the UAR v3 box) a big clip on the top holding both parts together - wee bit fiddly to remove but doable with some force and not too much swearing. 

Inside things are pretty simple - three gears, AR latch, cyl/piston and trigger. I removed the cylinder as I wanted to check the seal on the head. Holding my finger against the nozzle and pushing the piston I was pleasantly sueprised to find an excellent seal - no further problems there. A good spray of silicone in the cylinder and then checked the gears. There wasn't much grease in there - I was expecting a mess - so I sprayed some white lithium grease on the gears and shims and, satisfied all was well, went about putting it all back together.

The infamous AR latch was actually quite simple to keep in place, the trigger was fiddly but got there in the end after holding it all down firmly in place and screwing the shell together again. The big clip was then slid over the rail at the top of the box to keep it all together - simpler than removal - and then the selector levers were put on again.

Next, I examined the hop unit, which was clear there was an air leak there - the hop rubber slid out way too easily, so I added some electrical tape I had lying about and instantly solved the issue. After putting it all back together test shots were now reading 1.07j - back to what the gun was before this started (power dropped to 0.85j and dropped low as 0.3 when any hop applied).

So, first time teching experience. My thoughts... There's a lot of fear around AEG internals - having seen first hand and done work, it's honestly not that hard. Granted different gearboxes will have completely different layouts but honestly, I found this pretty simple. Even without the YT video I reckon I'd have managed OK.

Secondly... quite a few little bits to lose. Clean, flat, well-lit work area is an absolute myst, along with little storage cups or similar for stopping all those wee bits getting lost. I briefly goofed by losing the hop nub in the carpet - wife and kids dustracting me, they got the blame - 20 minutes of much swearing and anxious hunting ensued before it was found safe and well.

Thirdly, I achieved this with basic household tools. I'm sure there's better gearbox lubricant than white lithium but that's what I had in the garage and I'm sure it won't do harm. It certainly sounds smoother and quieter cycling than previously. My view is anyone with the most basic mechanical knowledge and with a set of poundland screwdrivers could fix an AEG. I'd go as far as say I enjoyed it and it's certainly helped demystify these mysterious machines so many of us are scared to touch.

Eezer G

 

[Rogerborg]

quite a few little bits to lose. Clean, flat, well-lit work area is an absolute myst, along with little storage cups or similar for stopping all those wee bits getting lost.

1000,000,0000%  And magnets, magnets, magnets.

 

[Davegolf]

Its worth checking your bucking to nozzle seal, this is done by having the gearbox set such that the nozzle is in its most forward postion, then push the hop unit assy into the front of the gearbox, if you now blow into the exit end of the inner barrel it should be completely air tight.

This will highlight a poor seal between;

Bicking to barrel/hop assy

Nozzle and bucking lips

Nozzle to cyl head

Piston to cylinder

 

[Ebeneezer Goode]

Thanks @Davegolf - in this case the leak was a loose fit between the bucking and hop unit, however I did also check the hop-to-gearbox mating as that's the next most obvious culprit for a leak. Very good point though.

And @Rogerborggood tip re: magnets!

Haven't had the V2 in my M933 apart yet but it's working fine - not going to muck about with that unless something goes awry. Only regreased the V3 box as I had it apart for investigation and although I (correctly) suspected the hop unit I wanted to check all else was OK. No stripped or damaged teeth, metal shavings etc and compression/seals all good. Certainly puts any claims to bed about APS' supposedly keech build quality, I was pleasantly surprised, gearbox seems a well built and solid unit.

 

[Davegolf]

PS white lithium is fine for the gears, just use something like Superlube, TechT or similar for the compresson parts so they dont dry out and bind up/drag which would result in a stripped piston or similar.

 

[Ebeneezer Goode]

I sprayed some silicone lubricant in there (home bargains, handy for the treadmill) so hopefully should last a while.

 

[Skara]

There's a lot of fear around AEG internals

Yeah, it's a silly simple mechanical system.

People just need to realize it's three gears, a piston, an electrical switch of some sort and it doesn't take a degree in nuclear physics to work on it

 

[Dan Robinson]

They're bastard fiddly though when you have chubby fingers, and in my case very little feeling in one thumb

 

[RostokMcSpoons]

I think I spent about 3 or 4 hours just trying to get the trigger spring back in place when I first took a V3 apart.  I also had a problem with the trigger shuttle container jumping out of place whenever I closed the shell.

I didn't have a quick change spring so having to deal with a lot of stored energy in the system encourages the possibility of a 'RUD'

So maybe Ebeneezer , your comparatively easy time is down to the particular components. Essentially you're quite correct, there's little in the big picture that's really all that complicated... The devil is very much in the details.

 

[Ebeneezer Goode]

They're bastard fiddly though when you have chubby fingers, and in my case very little feeling in one thumb

Can't say I disagree, some fiddly wee bits to lose if you're careless.

I think I spent about 3 or 4 hours just trying to get the trigger spring back in place when I first took a V3 apart.  I also had a problem with the trigger shuttle container jumping out of place whenever I closed the shell.

I didn't have a quick change spring so having to deal with a lot of stored energy in the system encourages the possibility of a 'RUD'

So maybe Ebeneezer , your comparatively easy time is down to the particular components. Essentially you're quite correct, there's little in the big picture that's really all that complicated... The devil is very much in the details.

Getting the trigger to seat properly in the shell to allow both sides to close properly was the most fiddly point of the whole exercise. I somehow managed to align the three gears in their bearings in the shell before slotting in the trigger and getting both sides closed with each other.

Also I have a QC spring which I'm sure makes things a lot easier. My Lancer also has the same feature.