Sudden Leak in Ball Lock

[TenaciousTinkerer]

Hi all, first post, I'll post an introduction in the appropriate forum when I have a free minute. But first, I'm a bit stumped on this one.

I'm old at brewing but new to kegging. Finally pulled the trigger on a kit from keg connection, tank, regulator, used keg and hoses.

The used keg came to me in good shape. After a week of sitting, I pulled the pressure relief valve and sure enough it had been holding pressure. Smelled like pepsi but no big deal. cleaned it out with PBW, starsan and purged with CO2. Then I racked a batch of mango dunkelweissen into it, set the regulator to 20psi and let it rip. immediately heard hissing from the keg. So I sprayed starsan around everywhere until I saw it coming from the main hole up top (not sure of the term, but the opening with the clasp lid). I swapped out the gasket with a new one and still got hissing and bubbling. With some finessing (read as: repetitive unlocking, repositioning and relocking) I got it to a point where bubbles wouldn't come up.

Fast forward two weeks. Everything had been fine. Beer was carbed nicely. But the next few days I noticed the beer starting to go flat, the regulator was all of the sudden in the red (had been completely full) and jumped down from 14psi to 8psi. I turned it back up to 14psi and heard the gas enter the keg and then stop. This morning I went to check on it all and the tank was completely empty and at 0psi.

Pulled the release valve on the keg and very little came out.

Is there some kind of secret ritual involved with closing these keg tops? Am I just doing it wrong? Or should it be relatively painless, and maybe I have a leak somewhere else? Or maybe the Keg itself is defective? Which doesn't make sense since it got to me holding pressure just fine. Unless it was only holding 8psi of pressure and anything above that causes a leak?

Thanks for any guidance.

 

[homebrewfinds]

I would take a hard look at the gas post o-ring. That's a pesky spot to check for leaks since it's only in play when a QD is connected and, it's difficult or impossible to check for a leak when the QD is on. A couple resources... check out my post on the pressure gauge method of checking for co2 leaks and here is my post on bulk oring sources and part numbers. I would grab extras, so you can replace as needed.

 

[Cavpilot2000]

Yeah, with an older keg, you are best off replacing ALL of the O-rings: Main gasket, 2x post o-rings (the ones your quick disconnects slide over) and 2x dip-tube o-rings (you have to take the posts off and pull the gas and beer tubes out).

Replace them all for peace of mind.
Also, occasionally the legs on the main lid get bent/weak and don't put enough pressure pulling the lid up. That could always be an issue. Williams Brewing also sells oversized (extra thick) main gaskets for the lid. I've heard they can help.

 

[IslandLizard]

Sorry to hear you lost your tank...

There are various "tricks of the corny trade" to set the lid.

When everything is (apparently) sealed up, always inspect for any leaks. Spraying or dabbing Starsan reveals a lot, except that failing o-ring on the gas post with a QD on it.
Also use keg-lube, quite liberally.

I have a few kegs with some issues, they are marked clearly, a piece of blue or green painters tape with notes. 2 kegs have a gas poppet that won't always seal automatically when removing the QD, letting a tiny bubble out every few seconds. A short push with a nailset on the poppet seats it correctly, usually.

 

[Cavpilot2000]

Oh yeah, forgot about the poppet O-rings!
SO there are 7 O-rings (including the main gasket) on each keg. When you get a "new" used one, my SOP is to replace them all from the start (except I do have a few I didn't replace that poppet O-ring on).

 

[IslandLizard]

replace them all from the start (except I do have a few I didn't replace that poppet O-ring on)

Because... the original 3-prong poppets (on older kegs) don't have replaceable o-rings?
It's remarkable how well those "o-rings" hold up over the years, though.

I hate the universal springs/poppets, but at least the o-ring is replaceable.

So is the poppet o-ring in QDs. I also bought several spare QD repair sets, just in case. Haven't needed them the 6 years I've been kegging.

 

[McHop]

I had this issue a while back. I replaced all the O-rings, used keg lube liberally on the hatch O-ring. I then cranked my CO2 to 50-60 psi and set the lid, checked for leaks, then set it down to 12 psi to carbonate. I was told that since the cornys used to hold soda at a higher pressure, you really need to set the lid with a higher pressure. Hope you find your leak, there is nothing more frustrating than losing a tank.

 

[Tobor_8thMan]

The used keg came to me in good shape. After a week of sitting, I pulled the pressure relief valve and sure enough it had been holding pressure. Smelled like pepsi but no big deal. cleaned it out with PBW, starsan and purged with CO2. Then I racked a batch of mango dunkelweissen into it, set the regulator to 20psi and let it rip. immediately heard hissing from the keg. So I sprayed starsan around everywhere until I saw it coming from the main hole up top (not sure of the term, but the opening with the clasp lid). I swapped out the gasket with a new one and still got hissing and bubbling. With some finessing (read as: repetitive unlocking, repositioning and relocking) I got it to a point where bubbles wouldn't come up.
Thanks for any guidance.

If the lid doesn't seal one way simply turning 180 degrees usually seals. When trying to get the lead to stop was the lid turned?

 

[TenaciousTinkerer]

Thanks for all the advice guys! I have some box wrenches on the way and have a couple hours carved out tomorrow after work to get to the bottom of this. I'll try all of your suggestions one by one, starting with replacing all gaskets and ending with the high pressurization test.

I did find out by trial and error that flipping the lid 180 degrees helps. That was actually how I got it sealed the first time. Took me damn near 20 minutes to do though lol. Will post back after tomorrows session.

 

[TenaciousTinkerer]

I had this issue a while back. I replaced all the O-rings, used keg lube liberally on the hatch O-ring. I then cranked my CO2 to 50-60 psi and set the lid, checked for leaks, then set it down to 12 psi to carbonate. I was told that since the cornys used to hold soda at a higher pressure, you really need to set the lid with a higher pressure. Hope you find your leak, there is nothing more frustrating than losing a tank.

Question - does this mean have the tank ON and flowing gas while you set the lid? or set the lid and after its clasped, flow with 50-60psi?

 

[McHop]

Question - does this mean have the tank ON and flowing gas while you set the lid? or set the lid and after its clasped, flow with 50-60psi?

set the lid to the keg, hit it with 50-60 psi until it equalizes then reduce the psi.

 

[TenaciousTinkerer]

set the lid to the keg, hit it with 50-60 psi until it equalizes then reduce the psi.

Got it, thanks. Gonna try that too after everything is all reassembled.

 

[seatazzz]

+1 to keg lube. I still have the original tube I bought with my first keg; it doesn't take much, and I usually only have to reapply it every third use of the keg. Mainly because that stuff is pernicious to get off your hands, NOTHING but time gets rid of it; I soak the lid in starsan while the keg is filling and the lube is still there. I've also noticed that my lids will only seal one way; if I get a leak once I put pressure on, turning it 180 degrees usually does the trick.

 

[TenaciousTinkerer]

Well after a couple of days of teardown and repair and a week of testing to make sure it was fixed, I found the following things wrong with the keg from kegconnection:

1: Liquid post rim was bent where the qd latches on
2: gasket on gas side dip tube was completely trashed
3: lid had a ding on it preventing full seal.
4: gas poppet was getting stuck open

#1 and #4 I don't believe caused active leaks, but were concerns so I addressed them anyway
#2 - easy, replaced the gasket
#4 - used set of pliers to gently bend the lip even with the rest of the mouth

used keg lube at the advice of all of you, and it has now held 30psi for 7 days.

Lesson learned. ALWAYS test and rebuild your used kegs the day you get them.

On the bright side, I was able to use the oxidized mango dunkelweissen to marinate a bunch of hot sausages, grilled them up with hickory, reduced the rest with some onions to make a sauce. Sides of classic mashed potatoes and shredded carrot salad (german style). Only ended up 'losing' about a gallon from the keg and the family enjoyed the sausages, so, crisis averted

Thanks for the help