Having a keg of beer spraying all over your house can get you a little out of whack in a hurry. I have a cornelius and a firestone keg, both have different sized. The cornelius I could use an adjustable wrench. The firestone keg I had to get a socket. Home depot doesn't have it. Lowes did, it was a kobalt brand socket, over near the dremel tools. I THINK it was 11/16ths, but I did the untechnical thing and took my keg in and tried them until I found it. Hope this helps Definately go in and replace all of the o-rings and the poppets. Hell just replace the entire post assembly really. Come to think of it I ones I put new poppets in and o-rings still leak Need new posts I guess.