Help with motor terminals?

[BGrail25]

I've been having a few issues with my JG M4. Basically, it seems like the battery doesn't have enough juice to pull back the piston, and it jams.
At first I thought it was the battery. Then, I tried to re-lube the gearbox with no real luck. I then figured out the motor height in the grip had something to do with it.
Finally, I know what's wrong. The problem is one of the terminals (positive, or red) keeps slipping off or something when the plate is put on. The original wire clip (or slider... whatever it's called) broke off, so I replaced it with a little bigger one. I put on shrink tube so it's exactly the same.
The problem has to be with the bottom cover. When I use my thumb to press it in, the gearbox will fire fine. When the cover is put on, it will work for a while but then stop.

In anyone's experience, is there something I can do to hold it on? Like some kind of adhesive or special way to clip it on?

[coach]

get the proper sized terminal connector.

[BGrail25]

It still did it with the old one though. It's not like it's too loose, it's actually quite tight.

EDIT: Hold on... I guess that makes no sense. I guess I mean it seems tight enough not to fall off.

[coach]

your original connector kept slipping off because it needed to be crimped to fit tightly.

the larger one is likely not fully contacting the motor terminal and needs to be replaced with the proper sized part. or it's not soldered properly and is loose.

[BGrail25]

Hmmm... That makes sense. Thanks dude!