Holding Tank Fitting Leaking

[NC-Ray]

Hello to all,

The fitting plate in the top of my fiberglass holding tank is leaking . The boat is a 1992 40 foot Hyatt (Asian) Sundeck. The plate is approx. 6 inches in diameter, is on the top of the tank,and is held to the tank with 8 nuts that attaches to studs from the tank. There are two lines from the heads, a pumpout line and vent all on this plate. It appears the PO ran some type of caulk around the plate. It is NOT silicone.. I was thinking of lifting the plate and make an attempt at resealing.
I assume it has a rubber gasket that is likely brittle and allowing the leak. Can anyone recommend a "form a gasket" type material that I could possibly use in this application? I have also considered butyl tape.

Thanks

Ray

 

[rwidman]

Hello to all,

The fitting plate in the top of my fiberglass holding tank is leaking . The boat is a 1992 40 foot Hyatt (Asian) Sundeck. The plate is approx. 6 inches in diameter, is on the top of the tank,and is held to the tank with 8 nuts that attaches to studs from the tank. There are two lines from the heads, a pumpout line and vent all on this plate. It appears the PO ran some type of caulk around the plate. It is NOT silicone.. I was thinking of lifting the plate and make an attempt at resealing.
I assume it has a rubber gasket that is likely brittle and allowing the leak. Can anyone recommend a "form a gasket" type material that I could possibly use in this application? I have also considered butyl tape.

Thanks

Ray

My first thought is that if something attached to the top of the tank is leaking, the tank is overfilled and the first thing you should do is get it emptied.

After that, I would do what you are considering, remove the plate, clean everything really well and reseal and replace it. I would think a good marine sealant (but not 5200) would work well.

 

[psneeld]

If you can find some old neoprene or buy a small piece, it would make a good gasket. Rubber would work if a softer rubber.

 

[NC-Ray]

The tank is not overfilled as I just pumped it.. I think the waste water is running outwards on the underside of the plate and leaking..

 

[hmason]

I had a similar issue and found that the vent line was clogged. As a result, when you flush, the air in the tank can't escape and you are pressurizing the tank. This results in moist effluent "air" to escape around the plate and the vent line fittings. Try clearing the vent line before removing the plate.

 

[NC-Ray]

Thanks. Good idea. I will try that tonight

 

[Patemey]

What Howard said.

But if that doesn't do it and if you wanted to try and seal it without removing the plate, put the pump out on it and suck to create/keep a negative pressure, then put sealant around the plate and let the negative pressure draw the sealant in. You may need to sporadically block the vent line to get more negative pressure to draw in more of the sealant.

 

[Xsbank]

Put some of this on your upper lip before you undo the plate...

 

[ranger58sb]

When I've fitted new holding tank level sensors, we just pumped and rinsed a few times in advance. Then let some KO or Noflex work for a bit... and had no particular odor at all.

-Chris

 

[rwidman]

What Howard said.

But if that doesn't do it and if you wanted to try and seal it without removing the plate, put the pump out on it and suck to create/keep a negative pressure, then put sealant around the plate and let the negative pressure draw the sealant in. You may need to sporadically block the vent line to get more negative pressure to draw in more of the sealant.

Attempting to seal something like that from the outside almost never works and you're just making a bigger mess to clean up when you finally decide to do it right.

This looks to be a pretty simple repair.

 

[HeadMistress]

Before you do anything else, clear the tank vent...you won't be able to pump out if it's blocked. The vent thru-hull is the most common location for a blockage. Use a screwdriver blade, ice pick--whatever works--to scrape out whatever is in it. Although blockages rarely if ever occur in the vent line, a filter in the vent line will turn into a blockage if it ever gets wet...which can easily happen if the tank is overfilled. Remove it if there is one.

Once the vent is clear, pump out and thoroughly rinse out the tank. Then remove the plate and clean the underside of it and the tank under the flange. This will also give you a good opportunity to inspect the discharge pickup tube for deterioration that indicates a replacement is needed (highly likely if the tube is metal, not so much if it's PVC). Make a gasket if you haven't already done so, put it down and replace the plate.

 

[NC-Ray]

Thanks Everyone

Thanks everyone for the advice. What I actually found was NOT a leak on the tank. My head has a 1" outlet hose and the PO adapted to 1 1/2 inch hose with a PVC barb fitting that was installed under the head in a hidden area. The liquid was running under the floor, ran down a bracket that holds the tank and made it appear the top of the tank was leaking. I am now drying it out and may try something like Natures Miracle to head kill the remaining odor. Maybe I should just buy Peggy's book . I will then replace the hose and we should be good.. And the adapter will be installed where I can inspect it!.

 

[HeadMistress]

My head has a 1" outlet hose and the PO adapted to 1 1/2 inch hose with a PVC barb fitting that was installed under the head in a hidden area....

Eliminate the adapter by replacing the discharge fitting on the toilet with a 1.5" fitting (available from Jabsco, straight or 90, whichever you need), then run an unbroken 1.5" line to the tank.. Then THOROUGHLY clean every inch of the area where you've had a spill using just detergent, water and (gasp!) elbow grease. Let it dry...then, to eliminate any residual odor, apply PureAyre PureAyre (Nature's Miracle won't work) and let that dry.

If it were my boat, I'd also do everything I recommended in my previous reply....now and about every 5 years.

Maybe I should just buy Peggy's book .
Just click on the title in my signature

Peggie Hall
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

 

[NC-Ray]

Thanks Peggy!