Originally Posted by retrograde
Beverage Elements are great folks to get a corny keg from. They're sending me a replacement lid + pressure relief valve at no charge.
Got my replacement pressure relief valve and my keg is finally holding pressure.
I also had to replace the dip tube o-rings under the gas and liquid posts. A soap-bubble test revealed leakage. To get the ball lock posts off, you typically need a large 7/8" or 11/16" wrench or deep socket (for pin-lock, you need a special tool sold by microbrewing sites). Sometimes, you need the wrench/socket to have 12-points instead of 6-points. My gas post was 7/8" with a 12-point star pattern (unusual for a Cornelius ball lock keg like mine, the star pattern is usually found on Firestone ball lock kegs).
I found this handy ratcheting box-end wrench at Sears with 7/8" and 11/16" ends. Perfect for this job and cheap (on sale now for 8.92)!
If you get more than one keg, try to get the same brand so you can share parts (Cornelius, Firestone, etc.). The threading on the posts and the height of the poppet valves are different depending on the brand.
Here is a great link that lists the different thread types and shows pictures of the different poppet valves: