TM MP5 - V2 gearbox (I think)

[magicaldr]

Hi, just after some views. My MP5 died yesterday, motor is spinning but nothing is moving inside and loud whine noise as you would expect. General view on the field was stripped piston or gear. So I have a few bits of advice I need, after I check its not something simple like gear on the motor is stripped or similar.

1. Should I even attempt repair?

Having looked at vids on TM disassembly and V2 gearbox stuff it looks like a chalenge, but not sure it beyond me. However if a few techs out there say dont touch with 10 ft cattle prod I will certainly take that on board.

2. Would this be a good time to simply replace all the gears/piston with more solid aftermarket ones? Can anyone suggest decent set / upgrade kit (and somewhere to buy it?) I am not after more power, higher ROF would be nice and or quieter internals.

3. If its all in bits, is this the time to also look at fitting a MOSFET, or am I saving up more woe...

Its a second hand gun from the forums (here) so no warranty to void. If anyone in Surrey can suggest a local tech who is reasonable (including themselves) open to that as well

 

[Rock-climby-Dave]

get a techie to fit a new gearset/piston and MOSFET whilst he's at it.

well worth the effort to get it running again.

and if you can, ask him to put a 'poor quality' (ie, one that is weaker than the gears - all plastic teeth etc) piston in so if this happens again you KNOW it's the £10 piston and not the £40 gears.

 

[Deva]

Not sure if I've missed something, but have you tried adjusting the motor height? It sounds like the motor is just spinning freely (not sure how loud you mean by 'loud whine noise' )?

 

[magicaldr]

Not sure if I've missed something, but have you tried adjusting the motor height? It sounds like the motor is just spinning freely (not sure how loud you mean by 'loud whine noise' )?

Nope you didnt miss anything, good first test which was suggested on Sunday and sadly doesnt seem to have helped (Sorry my fault, always list what you tried already).

Sound seems to be from top of gears as opposed motor as far as I can tell. I want to have a nose and see if I can spot anything obvious before sending away to a tech. From chatting seems a friend of a friend is an absolute guru on all things that go bang so hopefully I cant get myself into too much trouble.

Wish this as simple as my ICS, changed spring on that no issue. This one may take a bit more time I think.

 

[magicaldr]

Ok, I have considered and bitten the bullet (or should that be pellet?). Mainly as I really want to understand how the gearboxes work so better to play on this old V2 than touch any of my newer guns. Worst case I will end up replacing the whole box with a pre-upgraded after market one.

I have safely got the MP5 apart, nothing broke and all screws etc stored in box with the small bits I was warned tend to fall out and get lost. Hoping there will be no issues with re-assembly. Time will tell.

The gearbox has been likewise split, I now can confirm the middle gear was the issue having lost its teeth in one spot. My plan is to clean up the insides fully and replace all 3 gears with a basic steel set. The bushings (plastic) have also snapped on the central gear, so I plan to replace them all. I may also add a basic non braking mosfet as money is tight right now and I want a new £350 gun in a couple of weeks (which I wont play internally with).

Now for the question, there are 3 apparent sizes of bushing: 6, 7, and 8mm depending on gearbox. What bit do I measure to ensure I buy the right size of metal replacement? I am guessing its across the hole left in the gearbox shell and that standard TM V2 boxes would be 6mm (which is what I measured).

Its just a little harder to measure the bushing itself, since we talking on a mm either way to need a diff size so being over cautious.

 

[RR01]

Ok, I have considered and bitten the bullet (or should that be pellet?). Mainly as I really want to understand how the gearboxes work so better to play on this old V2 than touch any of my newer guns. Worst case I will end up replacing the whole box with a pre-upgraded after market one.
I have safely got the MP5 apart, nothing broke and all screws etc stored in box with the small bits I was warned tend to fall out and get lost. Hoping there will be no issues with re-assembly. Time will tell.

The gearbox has been likewise split, I now can confirm the middle gear was the issue having lost its teeth in one spot. My plan is to clean up the insides fully and replace all 3 gears with a basic steel set. The bushings (plastic) have also snapped on the central gear, so I plan to replace them all. I may also add a basic non braking mosfet as money is tight right now and I want a new £350 gun in a couple of weeks (which I wont play internally with).

Now for the question, there are 3 apparent sizes of bushing: 6, 7, and 8mm depending on gearbox. What bit do I measure to ensure I buy the right size of metal replacement? I am guessing its across the hole left in the gearbox shell and that standard TM V2 boxes would be 6mm (which is what I measured).

Its just a little harder to measure the bushing itself, since we talking on a mm either way to need a diff size so being over cautious.

Quick way to tell. If the existing bush slides down the inner barrel, it's 6mm. If not, 7 or 8. Depends on how old the gun is but less likely to be 8mm if it's more than a few years old.