Out post keeps leaking

[h22lude]

I bought two used kegs off a soda company recently. One of them I just pressure tested and it was leaking from both posts. I went and bought vaseline and that fixed the air post but the beer out post keeps leaking. It is leaking out the bottom where the post meets up with the keg. I lubed the dip tube o-ring and the poppet.

What else can I do? Oh and these are brand new o-rings.

 

[malkore]

my initial guess is the poppet isn't seat right, has a bad seal, or is worn an needs replacing.

it might not even be the right poppet style for the keg.

 

[h22lude]

The poppets and posts came with the keg...and I believe he still used that keg for soda so I would assume it was right but I guess I can't assume that.

How do I know if the poppet is right for the keg?

Are the poppets interchangeable with the posts or is there an air poppet and a beer poppet?

Edit: so I switched the two poppets and the beer out post is still leaking and the air post is fine so I would think it wasn't the poppet. Could it be the post itself or maybe something with the dip tube and o-ring?

Second edit: Could it be that I got the wrong o-ring? These two look different.
http://www.austinhomebrew.com/product_info.php?cPath=178_40_271_560&products_id=1200
http://www.austinhomebrew.com/product_info.php?cPath=178_40_271_560&products_id=10799

 

[rcrabb22]

The poppets and posts came with the keg...and I believe he still used that keg for soda so I would assume it was right but I guess I can't assume that.

How do I know if the poppet is right for the keg?

Are the poppets interchangeable with the posts or is there an air poppet and a beer poppet?

Edit: so I switched the two poppets and the beer out post is still leaking and the air post is fine so I would think it wasn't the poppet. Could it be the post itself or maybe something with the dip tube and o-ring?

Second edit: Could it be that I got the wrong o-ring? These two look different.
http://www.austinhomebrew.com/product_info.php?cPath=178_40_271_560&products_id=1200
http://www.austinhomebrew.com/product_info.php?cPath=178_40_271_560&products_id=10799

Just buy the whole replacement O-ring set and switch them all.

You can make a spray bottle of liquid soap and water (heavy on the soap) and spray the posts to determine where they are leaking, from the poppets or the post itself.

OR

take some cardboard and wrap and secure with duct tape around the top to form a temporary water tight well. Fill it with water enough to submerge the posts and watch for the origin of the bubbles.

 

[SpanishCastleAle]

If it's leaking out the bottom of the post it's not the poppet. The poppet is what makes the seal at the top (the little hole in the top of the post). That's the only seal the poppet makes.

The thing that is making the seal at the keg/post interface is the o-ring around the dip tube. This is actually sealing two sealing surfaces done with one o-ring (see below). If this is an older keg that doesn't use o-rings (but rather flat gaskets and sometimes a nylon spacer) then ime it's more difficult to get replacement parts and more difficult to get them to seal.

The post, when screwed down onto the keg, should gently 'press' the dip tube all the way down and the o-ring should seal against the top rim of the keg port (this keeps pressure from inside the keg from leaking). Then the o-ring protruding from around the dip tube should make a seal against the inner surface of the post (this keeps the pressure inside the post from leaking). These surfaces must be smooth and the o-ring should have an 'o' shaped cross-section (that's why they're called o-rings).

 

[h22lude]

If it's leaking out the bottom of the post it's not the poppet. The poppet is what makes the seal at the top (the little hole in the top of the post). That's the only seal the poppet makes.

The thing that is making the seal at the keg/post interface is the o-ring around the dip tube. This is actually sealing two sealing surfaces done with one o-ring (see below). If this is an older keg that doesn't use o-rings (but rather flat gaskets and sometimes a nylon spacer) then ime it's more difficult to get replacement parts and more difficult to get them to seal.

The post, when screwed down onto the keg, should gently 'press' the dip tube all the way down and the o-ring should seal against the top rim of the keg port (this keeps pressure from inside the keg from leaking). Then the o-ring protruding from around the dip tube should make a seal against the inner surface of the post (this keeps the pressure inside the post from leaking). These surfaces must be smooth and the o-ring should have an 'o' shaped cross-section (that's why they're called o-rings).

Its definitely the dip tube o-ring. You think that second link would work well since the o-ring seems flat and thicker? The air in post isn't leaking so I assume the keg isn't an older style that is hard to seal. I think I just need a different o-ring. I might swap the two and see what happens.

How much should I be tightening the post down?

 

[SpanishCastleAle]

Its definitely the dip tube o-ring. You think that second link would work well since the o-ring seems flat and thicker? The air in post isn't leaking so I assume the keg isn't an older style that is hard to seal. I think I just need a different o-ring. I might swap the two and see what happens.

How much should I be tightening the post down?

That's a really good question...because it depends. Sometimes just barely tightening the post will get it to seal when tightening way down on it will cause it to leak. You shouldn't need to tighten it super tight to get a good seal. Some of my keg posts bottom out before I feel much resistance, but they seal. There have been times I've drank the entire keg only to realize I never tightened the posts past hand tight, but it sealed fine.

But you don't want it so loose that some twisting of the QD will loosen it enough to leak.

Are you saying the o-ring is smashed or is it a flat gasket? If it's a smashed o-ring just replace it.

 

[h22lude]

That's a really good question...because it depends. Sometimes just barely tightening the post will get it to seal when tightening way down on it will cause it to leak. You shouldn't need to tighten it super tight to get a good seal. Some of my keg posts bottom out before I feel much resistance, but they seal. There have been times I've drank the entire keg only to realize I never tightened the posts past hand tight, but it sealed fine.

But you don't want it so loose that some twisting of the QD will loosen it enough to leak.

Are you saying the o-ring is smashed or is it a flat gasket? If it's a smashed o-ring just replace it.

This one seems to need to be tightened a lot to make a seal. It doesn't bottom out.

The oring I have is new and seems to be nice and round. What im thinking is it might just be too small and unless I tighten it a lot, it wont make a good seal. Im wonderin if the post isn't fitting right.

What about using two orings or finding one that is a little thicker?

What I was saying is mine now is round but the one I linked was a thicker flatter oring. If the round one is too small maybe the flat one is bigger

 

[SpanishCastleAle]

I hadn't looked at those links. They shouldn't really call that second seal an o-ring. An o-ring, by definition, has a circular cross-section. If a seal is supposed to be made with an o-ring, generally it won't seal unless you use an o-ring. But the sealing surfaces must be smooth. Scratches, dings, even pitting can prevent a seal. Two o-rings will probably not work (or be unpredictable at the very least).

O-rings do come in different IDs and different cross-sectional thicknesses but the next size up will probably be too thick.

If you can swap posts from another keg that might help you rule out the post itself.

 

[h22lude]

I hadn't looked at those links. They shouldn't really call that second seal an o-ring. An o-ring, by definition, has a circular cross-section. If a seal is supposed to be made with an o-ring, generally it won't seal unless you use an o-ring. But the sealing surfaces must be smooth. Scratches, dings, even pitting can prevent a seal. Two o-rings will probably not work (or be unpredictable at the very least).

O-rings do come in different IDs and different cross-sectional thicknesses but the next size up will probably be too thick.

If you can swap posts from another keg that might help you rule out the post itself.

That is the next thing I need to try. I have another keg but it has carbed beer in it