How to Repair & Fix a Ball Lock Keg

Kegs can be a real pleasure to use. I can package fifteen gallons of beer in about an hour these days, my carbonation is always what I expect, and having draft beer always on hand adds an extra cool factor to gatherings at my house. I don’t have to store, clean, and de-label hundreds of bottles, and I never, ever worry about bottle bombs.

But kegs do have their little foibles, and knowing how to really work with them will improve your experience. I actually gave up kegging for a while and went back to bottling because I had so much frustration – these are the tips that got me back to kegging and happier than ever.
Have enough kegs. It’s easy to get pulled in by the low-cost kegging setups you’ll see here and there, but one or two kegs is really not enough. You’ll want enough to have several hooked up at any given time, a couple filled and ready to be rotated in, and a couple more waiting to be filled. My beer fridge has three faucets and holds a total of five kegs; I have ten or eleven five-gallon kegs (plus a couple 2 ½ gallon), and I think that’s about right. You don’t have to go whole hog right out of the gate, but definitely build your supply as you can.

Prevent Keg Issues with Proper Maintenance

Have the right tools. All of my kegs use the same wrench to get the posts off – 7/8 inch, 12 point. You might need a different size, or even several, depending on the kegs you have. Maybe get a set just for the brewing toolbox so you always will have them to hand. I also find that a long brush (1/2” diameter by about 36”) is invaluable for cleaning dip tubes. An old toothbrush can work well for other detail cleaning. An O-ring hook is such a simple thing, but it makes working on kegs so much easier that it’s well worth the few dollars it costs. A standard screwdriver is also useful.

Have the right consumables. I stopped kegging, as I mentioned earlier, because I neglected this step. Get a tube of keg lube. Order a bag of 100 O-rings in each of these “dash” sizes: 109, 111, 013; and a few 417 (these are for ball-lock kegs; pin-locks may be different). I like the silicone ones, but buna-N works just fine and costs less. Also keep an eye out for deals on universal poppets, and get a few of those, too.

Breaking Down And Cleaning Your Kegs

Tear down your kegs and quick-disconnects and deep-clean them. Do this when you get them, for sure, and every now and then after that. I suggest only disassembling one post at a time, as they are not the same and easy to reassemble incorrectly. At very least, be very careful to keep track of which post is which. Pull each post off the keg and remove the poppet from it. The dip tube under the post can come out, too.

Soak the post and poppet in PBW or Oxiclean, and clean the inside and outside of both dip tubes. Remove the pressure relief valve from the lid, and drop that in the PBW bath as well. Fill the whole keg shell with PBW or Oxiclean solution and let that soak for a few hours to a couple of days. Rinse everything well and inspect it all for cleanliness and condition.

Small O-rings are so inexpensive that they should be replaced with any sign of wear or cracking. If any O-ring is persistently discolored, or smells like soda syrup, just replace it. The 109 size goes on the dip tubes and the 111 goes on the posts. The 417 size replaces the keg lid seal, just in case there was any doubt. Every seal should get a light coat of keg lube as you’re putting things back together.

To disassemble quick-disconnects (QDs), just depressurize the line, then stick a standard screwdriver in that slot on the back and unscrew it. There’s a pin, a spring, and a tiny seal inside, plus the screw-in plug and the body itself. All of those bits should be soaked in PBW or Oxiclean just like keg parts, then rinsed, inspected, and reassembled. If the seal is pinched or worn, replace it with an 013 O-ring.

Fixing Leaky Kegs and Pressure Testing

Pressure-test your kegs. There are a couple of good reasons to do this with empty kegs. First, gas leaks more easily than liquid, so you’ll spot more potential leaks. Second, if you do have water or beer in your kegs as you test them, it can absorb CO2, which reduces pressure and can give the appearance of a leak where none exists. You’ll want to have a spray bottle handy, full of water with a little dish detergent in it – mix it so that it makes bubbles that last a while when you spray it on something. You can also use Star-San solution, but soapy water works a little better, in my experience. The upside of Star-San is that it won’t ruin your beer if some is left behind.

Turn your regulator up to 30 PSI or so, and hook up the gas line to pressurize the keg. Disconnect the gas line and spray every part of the top of the keg well. Make sure you wet every place there is a seal – poppets, posts, the lid, and the pressure relief valve. Keep an eye on it for a few minutes and make note of anyplace you see bubbles growing or multiplying. Depressurize the keg and disassemble affected areas, then replace parts or seals as needed. If you noted bubbles on top of a post, you may need to replace the poppet. Bubbles coming out from underneath a post may indicate a dip-tube O-ring needs replacing, or you may just need to tighten the post a little more – or it might simply be that the seal wrinkled a little as it was seated, and a little keg lube would help it seat more smoothly. Of course, bubbles around the lid indicate that the large O-ring may need replacing, and so on. Once you've addressed all those issues, repeat the test until you don’t see any more leaks – then, your kegs will be as tight as they can reasonably be expected to be. Make sure you rinse off any soap, and that keg is ready for use.

I also like to pressurize my kegs and then just leave them sitting in my garage, not hooked up to anything, for a few days to a week. Then I open the pressure-relief valve just a little bit. If they still have good pressure in them after this slow-motion test, it’s a good indication that they are tight. The more scrupulous way to do this would be to check the pressure with a gauge both before and after the long rest, but I’ve never put together the gauge to do this.

If you get through all of these and find that your keg still won’t hold pressure, it’s possible that there’s a tiny pinhole somewhere. Used kegs have almost always had hard lives in soda fountains, and even brand new kegs can have tiny pinholes in welds. To spot these leaks, get the whole, pressurized keg into the bathtub or swimming pool, and look for chains of bubbles rising from anyplace on the keg.

Pressure-test all of your gas lines, too. Leaking beer is pretty obvious – it makes puddles. Leaking CO2, particularly small leaks, is much less so. You can easily lose whole bottles of gas from these invisible leaks, though – I certainly have. The fix is to go through your entire gas-distribution setup with soapy water, the way you did all your kegs. Every single QD should be tested both while hooked up to a keg and while not hooked up – this tests the QD itself and also the O-ring on the gas post of the keg. Check every single connection of every single gas line, all the way back to the connection to the regulator. Wiggle everything, too – sometimes leaks only happen when a line is flexed, for example.

Regular Keg Maintenance

Clean your kegs after every use. You don’t have to do the deep-clean described above every time, but you definitely want to get some PBW through the system to remove gunk. I’ve found one of the fountain-style keg cleaners to be very helpful for this, but you could also just mix up some PBW or Oxiclean and push it through the system. However you do it, always rinse well and sanitize before refilling the keg.

If you use these techniques to tighten up your kegs and your gas system, you should eliminate or reduce to insignificance any leaks you might have that have been costing you lost CO2 and excess frustration. I’ve used these tweaks to take my kegging setup from useless to amazing. It’s really hard to compare in any meaningful way, but I used to get only a few weeks out of a five-pound CO2 tank (and I’ve heard stories about whole tanks gone overnight), and now ten pounds lasts me five to six months easily. The twenty-pounder is good for almost a year. You may find that you need more or less gas over time than I do, just because you may carbonate and pour more or less beer than I do.

You’ll also have cleaner kegs, reducing the risk off off-flavors and infection, so you’ll pour better beer. And who doesn’t love good draft beer?