Holding tank vent fitting

[keithonElan]

I'm lost here. Maybe I need a little more caffiene in my coffee. Maybe clean my glasses. Maybe I need to go for a walk to clear my head because something just ain't right.

Am correct in saying that the photo in post #14 is NOT your current situation and there is still a corroded fitting stuck in the vent ?

If this is the case, it is highly unlikely you will crack the spin welded fitting on the tank if you are undoing the corroded fitting as you have said in your post #17. Tightening the fitting is what causes the stress which may lead to cracking the welded fitting. If you meet too much resistance in trying to undo the corroded fitting, use a hair dryer on the surrounding plastic to ease the grip on the threads and release it. Maybe wrap cloth around the corroded fitting to insulate it to keep it cooler than the surrounding plastic.

Maybe also try :



........................................ before going the heat route as a last resort. Just be careful the penetrating oil you try doesn't dissolve the threads of the spin welded fitting. Try it elsewhere on the tank.

Thanks again. Yes I’m still planning the removal of the corroded fitting on the tank vent. This fitting is indeed metal (looks like brass) with its male end screwed to the plastic vent of the holding tank. As you suggested, I’ll ask the techs in the marina what they recommend.

 

[Tally Ho]

I was worried about taking the fittings out of my poly tank on my 1988 O’Day 322. I just wanted to remove them and rebed them…but I didn’t know much about how the fittings were installed. Turns out they were in the same type of bosses you have in your tank.

Just back out the elbow and I think you will be fine. If the sealant is super tight, then some of the ideas Ralph mentioned can be employed…but I bet it will unscrew easily.

Then, when you reinstall, use a good sealant, and tighten slowly and don’t over-tighten it. Use lots of sealant!

Below is a short video I made when I pulled my water tank and reinstalled.

Greg

 

[keithonElan]

I'd use a 90 degree sweep instead of a 90 elbow on a vent line 'cuz ideally vent lines should be as short, straight and rise no more sharply than 45 degrees. I realize that "ideal" is often impossible, but using a sweep will let the tank breathe (which it needs to do to prevent odor out the vent)...an elbow won't.

Ask your local yard what they recommend to use on the corroded fitting to free it up enough to remove it. You may need to let it soak awhile before trying.

--Peggie

I’ve ordered a sched 80 sweep 90 deg thread to barb fitting that should fit. I’m in Canada and my boat is now on the hard and winterized. Completion of this fix will now be my first spring project. Thanks again for your important thoughtful advice!

 

[keithonElan]

I was worried about taking the fittings out of my poly tank on my 1988 O’Day 322. I just wanted to remove them and rebed them…but I didn’t know much about how the fittings were installed. Turns out they were in the same type of bosses you have in your tank.

Just back out the elbow and I think you will be fine. If the sealant is super tight, then some of the ideas Ralph mentioned can be employed…but I bet it will unscrew easily.

Then, when you reinstall, use a good sealant, and tighten slowly and don’t over-tighten it. Use lots of sealant!

Below is a short video I made when I pulled my water tank and reinstalled.

Greg

Thanks Greg!