We just had the bulkhead (front and rear) repaired in Nacogdoches. We are now trying to track down a leak in the black water system. We think it was happening prior to the repair work and possibly as a result of the very cold temperatures this last winter. We emptied all of the tanks for testing and let it dry out (stop dripping). We did fill the gray water to 3/4 with a hose (to isolate the test - not connected to any water and fresh tank empty) and drained it with no apparent signs of leaking.
When we filled the black water with a hose, it filled up and starting leaking out of the bukhead. The tank meter only indicated 3/4 but we could see the clear water almost to the flange under the toilet. The tank meter never read full so we now know that is broken. Any thoughts on where to look for the leaking? Is there an overflow point?
Look at the seal where the toilet drop goes into the tank and the tank vent seal also. When repairing the floor they may not have gotten the seal installed correctly as they are a pain to get right.
Mike
Is that behind the panel in the same bay as the water pump (passenger side - just in front of the rear tires)?
Depends on the bathroom lay out but on our coach Yes the commode is on the passengers side and the vent pipe is on the drivers side. Now if it was leaking before the floor was replaced then you may find a crack in the tank edge that will require welding up.
Mike
Welding? Is the black tank plastic or metal?
Some type of ABS I believe. With the right stuff it should be able to be welded up.
Mike
Plastic. Based on the type of plastic you need a plastic welding rod that is comparable with the tank and a heat gun welder. Just across the way from our office is a guy that makes plastic water tanks for fire departments. He starts with flat sheets of plastic and welds them up.
Fill it to 3/4 full using the dark tank flush hook up.
If it still leaks then you can rule out the toilet flange and the vent pipe as they are connected to the top of the tank.
If it's a slow leak and you are lucky..... it could be the dark tank dump valve leaking around the connector rod.
Fred; I would open up the wall on the wet bay and do a visual of what is going on when you fill the tank to say 3/4. It could be leaking around the rubber connector that is coming of. the bottom of the black tank. If so, that is a fairly easy fix to remove and replace with new unless the clamp is loose and if that is the case, I would just tighten it up and check again. A bright light is your friend.
I know. That's a big job removing the wet bay wall with all of those things connected to it. They sure made it difficult. :(
My fear is that it is leaking at
both the flange/vent at the top AND a slower leak at the valve.
OK. We spent Saturday and Sunday tearing apart the wet bay! :o We just had the front and rear bulkheads fixed in Nacogdoches and now we have water leaking from the bulkhead! (See photo) We don't want to ruin the work that was just done!
We do know that we have leaks at the gasket on the top of the black tank. When we filled/overfilled the tank, water bubbled up around the gasket and flooded the bay. :'(
1. What sealant should we use to seal that?
2. Is the proper result of an overfilled black tank to have fluid in the toilet or is there supposed to be an overflow pipe?
We also believe that the faucet had a drip on the cold fitting. It was loose when we removed the connector. We are going to remove the faucet. It is a water source and we really didn't use it. There are are signs that the fittings on the grey polybutylene pipes might leak. We are going to replace as much of that as we can with new PEX tubing. With the faucet gone, there will be many less fittings to leak!
We also checked the Valterra dump valves. They don't leak when closed and hold fluid even under 3/4+ tank fill. They both DO have a slight leak when dumping. We plan to replace those but we'll need to find other posts for that!
Based on other posts, we also need to redirect the fresh water overfill to below the bulkhead!
We do plan to make a new panel design so that we can FREQUENTLY check there for any water/fluids! The goal/objective is to protect the rear bulkhead.
3. Are there any other sources of water in the bulkhead that we're missing?
Correct.
There is a vent through the roof.
So what is the best way to fix that pipe and gasket into the top of the black tank?
After it is cleaned, would a silicone caulk or self-leveling sealer work?
I would think silicone will seal against air escaping, but so sure it will hold against pressure of tank being overfilled since it will be on the outside. Don't know how much trouble to replace the rubber grommet
Use some Goop marine sealant............ and try not to overfill the dark tank.
Amazon.com: Goop Marine Adhesive and Sealant Clear 3.7 Oz : Industrial &... (https://www.amazon.com/Goop-Marine-Adhesive-Sealant-Clear/dp/B00JB6U02C/ref=asc_df_B00JB6U02C/?tag=hyprod-20&linkCode=df0&hvadid=642056799018&hvpos=&hvnetw=g&hvrand=10531671765106721548&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1015156&hvtargid=pla-1949705320473&psc=1&gclid=EAIaIQobChMIh4PyuKu6gAMVxEh_AB2tgQXaEAQYBCABEgJ5d_D_BwE)
Yup, best way to not have the black tank overflow is to make sure you don't overfill it!
If it gets that high you would be in deep sheet.
Mike
So you have a leak after you got the bulkhead repaired? Why didn't they address your leak at that time. The seal going into the black tank is replaceable once the toilet is removed. Pull the flange and reinstall new seal reinstall flange. Shower is gray water. Different chapter. New seal should work like the original for the next 25 years
Agreed.
But, a blocked vent would allow pressure to build and contribute to leaks.
Black Tank Gasket - Completed
So I spent Saturday and Sunday getting the new gasket on the black tank and the flange put back down. I did need to bevel the end of the ABS pipe and use silicone grease to get it all to work. Yes, not overfilling the tank is a great idea!
Dump Valves
I did spend Sunday getting the valves off. Argh. Getting the bolts off of the valves was very difficult given the space. The access to the nuts on the back of the valves was nearly impossible. Here's my question.
Q) Is the intention to remove the entire piece of sewer piping, replace the valves while out, and replace the entire assembly into the tanks with the clamp?
If not, I can't be assured that the valves are tightened enough to prevent leaks.
Unless any of the pipes are damaged, just clean up the valve mating surfaces and install the new valve.
Then look at opening up the fiberglass underbody to remove the water-soaked foam and dry out the metal.
Be careful to not over tighten the valve when installing the 4 bolts. It is possible to crack the housing as well. They don't take much torque to tighten properly. When I replaced the valves I got it all dried out, put dry paper towels under anywhere that might leak, and then ran water into the black and gray tanks and let it hold for a day or two to check for leaks before closing up.
Since you mentioned not reinstalling the faucet, or keeping it disconnected, you may want to cap it at the manifold valves. You would not want to inadvertently turn on a valve even if capped in the wet bay. I think we have used the faucet once. I keep it turned off at the manifold.
I hadn't thought about turning it off at the manifold, good idea. I use the faucet frequently to fill a bucket to get the bugs off the windshield and hook a hose up to it to rinse it off
So, I also discussed this with Chad at Foretravel tech support. He advised against removing the pipes from the tanks. He did say that he inserts the bolts from the back and has the nuts on the front to make it easier. He also uses a thin board to slightly raise up the pipes for better access. He indicated that he's done a bunch of these and it's not an easy task with the limited space.
This week I'll try to install the new valves and keep the vocabulary as family friendly as possible. :)
I am blessed with a DW that thinks very highly of me and is very encouraging and supportive! She's got more confidence in me than I do!
Don't go there! It's a long story. ::) :-[ >:D :-X
8/10/2023 Update
We did get the dump vales replaced and they tested out good! Yeah! :) I put most of the bolts in the back side and nuts on the front. Saying a prayer for peace and patience prior to the install helped a great deal. O:) It is a frustrating job. One thing that I found helpful was an inspection camera. It helped me see inside the tight spaces! Kudos to Foretravel Tech support for assistance as well. At the end of the day, the valves no longer leak.
As part of testing the black tank, we did fill it up pretty high (but not to the toilet flange). We still have water coming out the top of the black tank. It is not leaking at the (new) toilet grommet.
Q) What other things are on the top of the black tank? In this case, the water is coming from the top center about 2 feet in from the driver's side of the tank.
Thanks. With the wall in the wet bay gone, I can see that the rubber connectors to the tanks are in good shape and no leaks. :)
So we continued the effort on the black tank leak(s). We were able to reproduce a leak at the grommet for the vent stack (see photo).
Unlike the other grommet for the toilet, this one does not have a clear way to replace it. The entire vent stack is glued ABS pipe. There is no give. Is this a place where I need to clean it up well and cover it with a sealant? If so, what do you recommend?
It appears that the toilet down pipe is misaligned and correcting that would be problematic so let the suggestions come as they will. If it were mine I would clean it up and JB weld it as I don't see any reason for flexibility as the flange is glued with ABS,
That is the black tank vent pipe. Yes, it does look misaligned. I'll get a picture from a better angle. Now I wonder if it's been leaking since 1996. I am leaning strongly towards JB Weld.
I did get the grommet on the toilet side replaced and that is sealed tightly.
As long as the vent pipe is open at the top (not plugged up on the roof) then the seal at the bottom of the pipe should never have to hold any pressure. As long as the tank is not filled all the way to the top, that seal should only see the occasional splash. Like Justin suggested (Reply #15), I would use some type of
flexible sealing compound that would flow around the misaligned (rubber?) flange and fill the gaps. That would allow for some slight movement between the pipe and the tank, like when you are bouncing down rough roads.
But the most important thing to do is FIX your level sensing system so you don't EVER fill the black tank all the way to the top!If you can't get the stock level sensor working, then install a SeeLevel monitor. One way or the other, you should have the means to always know
exactly how full your black tank is, and
dump before it hits 100%.
RV Tank Sensors | Seelevel Tank Monitoring System | RV Upgrade Store (https://www.rvupgradestore.com/RV-Tank-Monitor-System-s/164.htm)
After some blood sweat and tears, ALL of the plumbing leaks have been resolved. Kudos to my DW for pushing for US to resolve them instead of the shop. It's all dry now. We found numerous leaks. We also replaced some of the grey polybutylene pipe and fittings with new PEX and fittings. Here is the list of leaks.
1. Grommet on top of black water tank at toilet (replaced)
2. Grommet on top of black water tank at the air vent (sealed)
3. Black water valve leaked when dumping (replaced)
4. Gray water valve leaked when dumping (replaced)
5. wet bay faucet connections behind panel (cold fitting was loose)
Instead of re-installing the wet bay faucet, we opted for a 10"x"10" metal access panel. Now we can check on it whenever we want just by opening the door. :) We had the bulkhead opened in Nac. and re-inspected. We also had them remove surface rust missed last time, apply rust-proofing (missed last time) and apply undercoating (also missed last time).
Lessons learned:
1. You really need access to behind the wet bay panel to inspect for leaks and confirm basement heater is operational.
2. An inspection camera is a great help ($70 on Amazon)
3. ALWAYS check behind the shop in Nac (no names but this applies to all shops) and verify their work! Insist on visual inspection and/or photos prior to things getting sealed up.
4. Replacing the dump valves is not easy but can be done.
5. It's great to have a DW that believes in you and pushes you past your comfort zone!
Fred,
Excellent job.
Now, get the water out of the basement floor sandwich so the rear bulkhead doesn't rot.
Brett,
Yes! The basement "sandwich" is all dry. It was totally dry when we got to xOT and they removed the fiberglass. We had been using all of the plumbing on the trip down there. Now it has rust-proofing on the metal and undercarriage spray to keep water out.