In my case I have Pepsi ball-lock type posts (Coke used the pin-lock type). The
In-post has a 12 point wrench pattern, while the
Out-post has a 6 point . (So you can confirm they are not installed opposite. And note that if you need to buy the 7/8 wrench to take them apart to clean you have to be sure to get a duel open-end/box-end wrench to be able to get both off. Youll note the wrench is placed upside down here relative to the proper wrench end.)
If you look at the post heads close you can see they are slightly different designs. The
Out-post has a bit more of a flange (& higher flange) and is about a mm skinnier. (The ball bearings lock around those flanges.) In theory this design keeps you from hooking them up backwards, but if you somehow do that, the thing will not blow up or anything (they are rated to 130psi) youll just be pushing CO2 to the bottom of the keg vs. the top. [Of course the C02 Tank itself is
very dangerous if you dont secure properly and somehow knock the top off, it could kill someone.])
I have a
red rubber o-ring on the
In-post of the keg, and a black on the
Out-post. Makes it easier to see after youve had a few. By recent tradition the new disconnects are all black for the Out and gray for the In. You may find older ones of different colors. Ive seen blue and red ones; presumably Pepsi colors.
I have a problem installing the CO2 disconnect every time when the o-ring is completely dry. But a little food grade lube (i.e. beer) might make it seem almost like it comes on and off too easy. (Be sure to sanitize the CO2 ball-lock before kegging, if you use the keg as a secondary, as I do, or if youre storing the kegged beer for long periods of time whoever can accomplish that.)
Im sure it doesnt hurt to replace all the rubber gaskets every now and again (by definition, a refurbish job), but Im on 20 years with these little 3 gal boys and only on my last brew did I get a little seep in one of the nipples. She wouldnt hold 18psi for forced carbonization. So I guess its finally time.
(Note be careful to not over tighten the posts with that big burly wrench. Snug is fine if you want the gasgets to last. And do NOT soak with bleach to sanitize stainless steel, if you value you kegs.)