A little method I use is to pull the skin a bit to the side when injecting pin, then release once in all the way, inject gear, wait 10-20 seconds as previously mentioned, then slowly pull out pin. By pulling the skin gently to one side before inserting pin, when you pull it out, it is like the pin has gone in on an angle and prevents the gear from leaking out as the skin closes back around pin as you pull it out.
Try it out. Shit I hope I explained that right and you know what I mean.