Keg won't hold pressure after changing rubber seals

[mrphillips]

I have a used corny keg, and it will NOT hold pressure - not even overnight. I changed the large rubber seal on the keg lid, and the external/internal seal rings on the in/out ports...but the SOB still won't hold pressure.

Is there a seal on the gas letoff thing (sorry, I don't know the part-name) that I can replace? Is that the most likely suspect?

I get married in a month, and was hoping to have a functioning keg to contribute some of my own flavor to the festivities.

Thank you for your help.

 

[day_trippr]

If the keg has yet to be filled with beery goodness, pressurize it and submerge the top in a big sink or a bath tub. You'll find the leak(s).

Yes, the Pressure Relief Valve has a poppet with a rubber gasket/o-ring.
You can obtain replacements from various places including here, being careful to choose the direct replacement type.

Otherwise...if you haven't tried it yet, it helps to apply a film of silicone lubricant (aka "keg lube") to all gaskets and poppets. And never fit a dry o-ring (eg: the O-rings under the dip tube flanges) as the odds of damage go up considerably. At least wet with water before installing...

Cheers!

 

[IslandLizard]

You mean the PRV (Pressure Relief Valve) on top of the lid?
Yeah, there's a small rubber seal under that too. It can be a small rubber disc, or a small o-ring around the stem. On the dome ones, you need to unscrew the plastic PRV from the bottom with a square driver.

If the leak is modest, you can see it when spraying water or Starsan around all the suspect areas. Or dunk the keg into a tub of water, like the bathtub. You can see bubbles where the leak is.

If the leak is larger you can hear it. If it's very small, again dunk into the tub, and watch for small bubbles.

When no Quick Disconnects (QDs) are connected, the outside post o-rings have NO function. It reduces your quest by keeping those off. Check the gas poppet for leaks. Spray Starsan on it. Push it in with as small screw driver or nail set, and see if it reseats correctly.

Is there beer in it?

 

[mrphillips]

Sigh. Yes, I have delicious beer in it. Since it won't hold pressure, I have no qualms about popping the lid off and checking out the PRV seal (thank you for the part terminology).

I'll check the keg tomorrow. My inpatients with alcohol leads me not to trust myself with a screwdriver.

Thanks for the info!

 

[IslandLizard]

Sigh. Yes, I have delicious beer in it. Since it won't hold pressure, I have no qualms about popping the lid off and checking out the PRV seal (thank you for the part terminology).

I'll check the keg tomorrow. My inpatients with alcohol leads me not to trust myself with a screwdriver.

Thanks for the info!

You can check any keg seal under water. It won't taint your beer as long as there's pressure within [poetical phrasing implied].

 

[day_trippr]

Mix up some Star San sanitizer and paint or spray it over the posts, lid and PRV.
You might catch the source of the leak.

Alternatively, if you're reticent about submerging the keg, wrap duct tape around the top of the keg, starting an inch or so below the rubber and working to the very top.
Congrats, you just created a man-made pond, which you can fill with sanitized water to check for leaks...

Cheers!

 

[mrphillips]

The wedding was a success, as was the beer! I changed out the pressure release valve (best $6 i ever spent), and the beer was carbed and delicious...hell, it was gone before the reception started! Thanks for all the advise.