Black Water Holding Tank Leaking

Robf said:
Update...two years later, I am replacing the entire tank that I attempted to patch. Although I haven't found a visible leak, the bilge does not smell right. I am guessing it is leaking under the tank and any visible stream is vaporizing in the heat. I have ordered the complete replacement from West Marine with all equipment already installed for about 1,100. Not cheap, but the tank alone was $780 without the pump, monitor, filter, or fittings, so it seemed to make sense to me to get the complete unit for a few hundred more. Will keep you posted how this replacement goes!
Rob
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if you still have odor in the ER after the new system is installed you may want to check the hoses...they can be permeated to the point the odor from the waste pases through the hoses and into the ER.....

good luck....

cliff
 
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Robf said:
Update...two years later, I am replacing the entire tank that I attempted to patch. Although I haven't found a visible leak, the bilge does not smell right. I am guessing it is leaking under the tank and any visible stream is vaporizing in the heat. I have ordered the complete replacement from West Marine with all equipment already installed for about 1,100. Not cheap, but the tank alone was $780 without the pump, monitor, filter, or fittings, so it seemed to make sense to me to get the complete unit for a few hundred more. Will keep you posted how this replacement goes!
Rob
Click to expand...

I did the same thing - bought the "loaded" tank with all the equipment. 'Course I had to unload the existing tank of it's 'load', first.

I agree with Cliff - hoses are suspect, too.
 
I have already pumped all out, but still getting odor. I plan on cleaning out the bilge which is full of suspect liquid. (no trail from the tank, but liquid in the lower bilge) I plan on getting the shop vac in the bilge and going to town. Dennis, any advice you have in pulling and replacing the tank?

Rob



Lazy Daze said:
I did the same thing - bought the "loaded" tank with all the equipment. 'Course I had to unload the existing tank of it's 'load', first.

I agree with Cliff - hoses are suspect, too.
Click to expand...
 
I am cringing here , sorry to hear you have to pull tank Rob. Mine has been holding since I started this thread, but after reading this, I am worried. I would have replaced if I could easily remove the tank. At a minimum, risers and manifold have to come off as well as hatch brace.
 
The tank itself can be loosened up enough to remove by the removal of just two screws (typically). It's held down, not specifically by screws, but by brass "thimbles" that are screwed to the deck and then the feet of the tank slide into the thimbles. You only need to remove the thimbles from the side of the tank that you will be removing it towards - even if it's just an inch or so to clear the other side.

It's been quite a few years, now, but I remember that I pressure tested mine to double check there was a leak. Although, it was pretty obvious and I really only did it "just because". Now, the stinker is, I can't remember exactly what I did. I may have used duct tape to seal holes, but I don't really recall. As far as pressuring it, I think I had made up a plug with a bike stem inserted into it. I put in just enough pressure to see the sides of the tank flex - probably just a few pounds. You may want to investigate doing this before removing and replacing.
 
I actually pumped the tank and filled with freshwater from the deck pumpout. I added blue deodorizer and waited. I found the stream of blue out of the rear of the tank. New tank is on order, but my concern is getting the tank out past the engine. I have loosened the tank previously to put the JB Weld in, but this didn't hold. Will I need to remove the exhaust hose at a minimum? Will a any other parts need to come out?
Rob


Lazy Daze said:
The tank itself can be loosened up enough to remove by the removal of just two screws (typically). It's held down, not specifically by screws, but by brass "thimbles" that are screwed to the deck and then the feet of the tank slide into the thimbles. You only need to remove the thimbles from the side of the tank that you will be removing it towards - even if it's just an inch or so to clear the other side.

It's been quite a few years, now, but I remember that I pressure tested mine to double check there was a leak. Although, it was pretty obvious and I really only did it "just because". Now, the stinker is, I can't remember exactly what I did. I may have used duct tape to seal holes, but I don't really recall. As far as pressuring it, I think I had made up a plug with a bike stem inserted into it. I put in just enough pressure to see the sides of the tank flex - probably just a few pounds. You may want to investigate doing this before removing and replacing.
Click to expand...
 
Aside from my boat, I don't think I've ever removed more than maybe two other tanks from boats - and not from a 340 with V-drives... and having the V-drives (as opposed to stern drives) won't help. Without being there and looking at it, I couldn't tell you for sure. I'd definitely give it a good honest try (rotating, twisting, turning the tank) though before I removed anything else.
 
Robf said:
I actually pumped the tank and filled with freshwater from the deck pumpout. I added blue deodorizer and waited. I found the stream of blue out of the rear of the tank. New tank is on order, but my concern is getting the tank out past the engine. I have loosened the tank previously to put the JB Weld in, but this didn't hold. Will I need to remove the exhaust hose at a minimum? Will a any other parts need to come out?
Rob
Click to expand...

Was it streaming from one if the corners? Did you put the JB weld on all four corners?
 
Just noticed that nobody mentioned the process of poly ethelyne welding. There is a kit you can get that has the welding gun, rods, and instructions. They are often used to repair poly bins used in fruit handling, and poly tanks also used in food processing facilities. Harbor Freight sells a version too thats less than $100. http://www.harborfreight.com/plastic-welding-kit-with-adjustable-temperature-96464.html Its basically a heat gun of sorts and special plastic filler rods. You clean and prep the surface with grinder and then weld the crack/hole with the plastic rod. It is far superior to glues and epoxies for this application.
Here is a good video on the basics. https://www.youtube.com/watch?v=HvV9a3lEe2g

Here is a vid on doing a poly ag tank, similar to a marine holding tank.https://www.youtube.com/watch?v=k_Fkhz2G9Is
 
Yes, I had used the JB Weld several years ago and it appeared to hold until now. I figure replacing the tank is the better long term solution.
Rob

sdleo26 said:
Was it streaming from one if the corners? Did you put the JB weld on all four corners?
Click to expand...
 
Dennis, thanks, I will definitely try every way first before pulling things apart!
Rob

Lazy Daze said:
Aside from my boat, I don't think I've ever removed more than maybe two other tanks from boats - and not from a 340 with V-drives... and having the V-drives (as opposed to stern drives) won't help. Without being there and looking at it, I couldn't tell you for sure. I'd definitely give it a good honest try (rotating, twisting, turning the tank) though before I removed anything else.
Click to expand...
 
Rob,

I removed the holding tank pump, unclipped the fresh manifold, and moved my stern drive overflow bottle to get my tank out, without removing the manifold or riser on my port engine. Hope that helps...

Eddie
 
Eddie
Unfortunately I have 8.1 liter engines with V drives. There is 11 inches of clearance between the deck and portside exhaust. Appears I will need to remove the exhaust lines that exit under the boat to get the clearance to pull and replace. What a crappy job! pun intended!
Rob

Water U Lookin' At said:
Rob,

I removed the holding tank pump, unclipped the fresh manifold, and moved my stern drive overflow bottle to get my tank out, without removing the manifold or riser on my port engine. Hope that helps...

Eddie
Click to expand...
 
Robf said:
Update...two years later, I am replacing the entire tank that I attempted to patch. Although I haven't found a visible leak, the bilge does not smell right. I am guessing it is leaking under the tank and any visible stream is vaporizing in the heat. I have ordered the complete replacement from West Marine with all equipment already installed for about 1,100. Not cheap, but the tank alone was $780 without the pump, monitor, filter, or fittings, so it seemed to make sense to me to get the complete unit for a few hundred more. Will keep you posted how this replacement goes!
Rob
Click to expand...
My tank is starting to leak. Was your new tank the same as your old tank
 
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Yes, I ordered the exact 28 gallon Dometic tank, which unfortunately still continues to put the embedded hardware in the bottom of the tank that caused the issue to begin with!
Rob
catfish54 said:
My tank is starting to leak. Was your new tank the same as your old tank
Click to expand...
 
Interesting this thread resurrects after so long. I'm really surprised nobody has opted for a hold and treat system or are the laws too restrictive?
 
Robf said:
Yes, I ordered the exact 28 gallon Dometic tank, which unfortunately still continues to put the embedded hardware in the bottom of the tank that caused the issue to begin with!
Rob
Click to expand...


Thank you. Maybe a new one will out last me.
 
Hopefully you won't be like me and spend 10,000 in upgrades to a boat and immediately sell it and buy another boat that needs updates!lol...Rob
catfish54 said:
Thank you. Maybe a new one will out last me.
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