Seized pumpout cap

[Dick Kobayashi]

In recent years, but not every year the bronze/brass cap on the pump out fitting becomes seized. Previously I have tapped on the slot edge with a cold chisel or similar and freed it but not this year. I am looking for advice on how to free it and also on how to prevent it.

[Jim Walsh]

I had the same issue a couple years ago. I drilled two holes in the cap so I could use the Groco wrench pictured below. I filled the underside of the cap with J-B Weld. Problem solved. I can post a picture of my modified cap in a couple days.

[Jeff and Sarah]

Try dry ice and a plumbers torch to expand the flange and shrink the cap. My diesel fill (same type of bronze fitting) seized over the winter. I was able to get it off the boat by removing it from the fill hose and I used a series of time in the freezer and heat with a torch to get it free. All previous efforts including PB Blaster and a variety of tools (legitimate, improvised, and those grounded in nothing more than hopes and prayers) failed horribly but the laws of thermodynamics came through for me. Years back I had the pump out cap freeze and after all efforts I ended up making a tool that was the same size/shape of the actual tool but it had a very long handle that offered enough leverage to lift the world.

Good luck- an annoying problem but one that can be solved!

[Sea Hunt Video]

Dick:

Another inexpensive option would be to attach a set of locking pliers to your deck key or a generic deck key. I would think this would be sufficient leverage to loosen the cap. Once removed, applying WD40 to the threads, etc. may help a little for the next pump out.

I said "inexpensive" because I assume you already have some type of deck key and a set of locking pliers.

[Bill Goldsmith]

Once freed up, apply anhydrous lanolin to the threads once a season to prevent future recurrences. Works great on turnbuckle threads, too. You can get a tub of this stuff at any pharmacy. Only downside is your hands smell like a sheep farm until you wash up.

[Steve Laume]

I would try PB Blaster and let it sit for a day or so. You can use an adjustable wrench on your regular deck key for leverage so there seems little need to modify the cap.

Once you get the thing open, it is time to make sure the problem does not reoccur. Bill has the right idea but I would also take the cap to an auto parts store and have them match up the O ring. Get a few extras so you have some spares and replace the ones in your fuel and water fills while you are doing them. Clean the threads, grease everything, put in nice fresh O rings and you will never have any trouble again. Once you have a good O ring seal the cap only has to be tight enough to keep from unscrewing, not cranked down so hard the it binds. This is especially important for your fuel fill as it will keep water out of your fuel tank. This is one maintenance item that is extremely cheap and easy to do, Steve.

[Dick Kobayashi]

Thanks all. The PB blaster worked after a while. That and taping with a cold chisel and light hammer final broke the seal. I am thinking that the O ring replacement is key as I fear it is the old, maybe original O, that is binding - threads look fine. I have had this problem several time and would prefer not to have it again.

[Sea Hunt Video]

Dick K.:

Lube the new 0-ring with silicone gel to keep it pliable.

[tjr818]

I would also recommend a very light coat of an anti-seize compound on the threads. The pump out is a very corrosive environment and those threads will need all the help they can get to stay trouble free.

[grluecke]

I put this stuff on every screw thread I ever see, near the ocean or not.

It's a little messy, so you have to use caution that way, but I'm pretty sure you will never have any trouble getting anything back off if you want...

https://www.pepboys.com/product/details/8975290/01036

[jen1722terry]

Sadly, our fill cap has refused to yield to all the above methods. We're getting some mechanical work done in the next week so we're having the mechanic replace the old fill with a new ss one, which we'll use anti-seize on religiously.

Jenn and Terry