How to reseal the black tank flange?

[Its Paid For]

ABS tanks are easier to repair than PDE tanks, but the trade off is they crack and leak a whole lot easier too. I still think that plywood had much to do with your leak, doesnt make sense to be flush against pipe over flange.

[Bruce and Jenna]

Originally Posted by rockintom

Bruce,

Please be more specific.....you say your repair didn't work.....is it still leaking at the fitting going into the black tank? or is it leaking somewhere else not visible until you get the belly blanket off? My leak was a grey tank and not the black. But the tank are basically the same except the black is about 1/2 the width of the grey. My grey tank is gone I traded the tank for some parts I needed for my rig. Just FYI my repair on the grey tank was only temporary as it started to leak just a little bit when we got rid of it. The crack in the ABS was in a very stressful area. I learned one thing throughout that experience. NEVER run down the road with anything more than "very little") liquid in your tanks (except fresh water....it is surrounded with a cage of angle iron and is pretty robust).

OK back to your issue.....answer my first request and we'll go from there.
BTW....I know a guy that just replaced his black tank with good results. He and I went back and forth with emails. I think I still have his email if you want to chat with him also. Let me know. rockin'

Thanks for the reply.

Black tank is leaking when full. I can see the results at the opening in the plywood around the flange. But not the leak itself. More results on the inside of the belly blanket, and the fluid has traveled back past the tank. I've not cut open the entire blanket to find where, 'cause I figure I must replace the tank in any case.

I talked with Jack. Found out the tank doesn't cost too much, so I ordered the entire kit of materials, excluding the probes, as I recently purchased Horst replacement probes. And ordered a full length of belly blanket, as mine is soaked with fluid. I figure I must replace the blanket and most of the insulation anyway.

Jack said that PI technician will spend 8 - 10 hours. [And they have a lot of nice tools and a lift.] After considering that info and your experience in your post, I have talked with our local RV tech to work on it with my assistance. This job is difficult and fraught with chances to really screw up.

Your thoughts?

And, yes, I sure would like to correspond with anyone else who has worked on this project.

[Lindaxtwo]

Oh Bruce,
I feel your pain on this one. We had cracks in our black tank two years ago and had to have replaced. Had an Excel dealer do it and was a nightmare. Biggest problem with our installation (and I still don't think it's right) is the point where the 6" line goes into the top of the black tank. Our tech rushed the time for the glue to set up before filling the tank with water to test the seal and it pulled apart. Then had to try to clean away glue and start over. I think it's a poor design overall and I think ours still has a little separation at that connection point as I sometimes smell black tank fumes. I've attached a picture of the crack around the connection. There were other cracks on the bottom corner areas too. As Tom said, I always travel now with grey and black tanks empty. Just too fragile an area. While you have the area tore apart, I would beef up the number of straps (as Tom did) and put the rubber tubing over the areas where it wraps/touches the sides of the tank to cushion it. We cut up strips of tubing for our repair but the tech refused to use them. Good Luck to you....if you're like us, it makes you half sick to think about dealing with it. Our repair was $1400 and a big botch job by an Excel dealer that I would have thought should have known how to fix these types of things. Live and Learn !

[87_Fixr]

Bruce, I might have missed this in the posts- is the cut in the plastic drain pipe just one cut, and then you pressed the pip down into the tank to create the gap, or did you make two cuts and then install the rubber coupler?
Reason for asking- if you made two cuts, are you sure that the pipe goes down into the tank far enough, and that it's not causing the leak because it's too short? It sure looks like a good patch job.
Its Paid For is right-

doesnt make sense to be flush against pipe over flange.

I hope the repair at the dealer won't set ya back too much.

[Bruce and Jenna]

Originally Posted by dnstclr

Bruce, I might have missed this in the posts- is the cut in the plastic drain pipe just one cut, and then you pressed the pip down into the tank to create the gap, or did you make two cuts and then install the rubber coupler?
Reason for asking- if you made two cuts, are you sure that the pipe goes down into the tank far enough, and that it's not causing the leak because it's too short? It sure looks like a good patch job.
Its Paid For is right-
I hope the repair at the dealer won't set ya back too much.

Thanks for asking.

I cut the pipe more or less in the middle, then slipped the collar into the gap. Did not cut alter the lower part of the pipe down into the flange at all.

I see stains on the plywood and carpet near the flange even without seeing fluid around the flange. When the tank fills up. I can only assume I have a crack at the top of the tank somewhere under the plywood. It pools on the top of the tank, thereby staining the plywood. I only see the fluid at the opening around the flange, but likely it's touching elsewhere. I have a sliding tray covering much of the floor over the tank, so I don't see that section at all.

Eventually it spills down the side, resulting in the fluid on the belly material.

From all these suggestions, I plan to add some plastic coated support straps, replace the gaskets on the valves, replace the belly material, replace the probes with Horst probes, and install a second tank washer. Maybe a waterproof remote camera with a light just for monitoring.

And I have good technician who will do what I ask, unlike the people that worked on the Lindas' rig.

Gonna cost some Franklins to fix, you betcha. Can't see that I have a choice tho....

[Bruce and Jenna]

Somewhere someone [Rockin'?] mentioned replacing the valve seals when disassembling them. What should I look for when I purchase the replacement seals?

[Bruce and Jenna]

Wait. I found it in a PM with Rockin. For the record
The seals are cheap. 3" and 1-1/2" Yours are Veltrerra(sp) and available at every RV parts store.....both sets should be less then $10.

[rockintom]

Originally Posted by Bruce and Jenna

Wait. I found it in a PM with Rockin. For the record
The seals are cheap. 3" and 1-1/2" Yours are Veltrerra(sp) and available at every RV parts store.....both sets should be less then $10.

Darn you're good! I've found anytime you diddle or disturb the black and grey valves as when you replace either or both tanks.....even though your valves didn't leak before......once disturbed the seals leak internally allowing stuff to leak-by the seals and out the pipe to the EZ Pivot. Major disappointer!!! rockin' Seals are cheap.....I keep them on hand.

P.S.One other thing that notes attention! The 4 screws that retain both black and grey valves should not be overtighten. Just a tad tighter than hand tight. Overtightening distorts the valve and flange, which will cause binding of the slide valve and/or cause external leaks. rockin' again-over and out this time for sure!

[Bruce and Jenna]

Turns out the tank was leaking from the flange after all. Couldn't see it up against the plywood. Guess I shoulda gone all the way by removing the sliding tray and cutting out more plywood. Who knew?

Prior to removal


Likely point of leak. Couldn't see it next to the sliding tray.


Took 5 hours for an excellent technician and I at Park Sierra to remove and reinstall the black tank. Also installed a second tank washer RIGHT IN FRONT OF THE OPENING FOR THE FLANGE [front end of the tank]. I won't show you a pic of the "cone" there. Obviously the tank washer that PI installs on the back end of the tank does not clean the front. I hope this will help to solve my frequent toilet clogs.

Did not take a lot of pics of the installation, as Rockin' documented his similar gray tank installation quite well.

Next week we will finish up by adding a piece of plywood between the straps and the tank for added support. Then replace the belly material.

One of two support bands for the gray water tank was broken. I installed four bands for the gray and three for the black. Haven't exposed the fresh yet, but likely I will add a band of two there also. Also added a set of Horst tank probes in place of the standard ones.

As Rockin' mentioned somewhere, PI installs the black tank above the gray tank at the center support beam. Couldn't pull out the black without removing the gray. Which would have meant cutting additional hoses to that tank. Instead, the tech used a Sawzall to cut the black tank out at the support beam. Then we remounted the black tank under the gray. Saved time and aggravation.

[rockintom]

Bruce......glad you gotta good guy helping you doing that dirty job.....bet your neighbors are lovin' ya. Good thing you're out there in the sticks and there is a lot of space! Keep us informed on the conclusion buddy. rockin'

[JohnRR]

Thank you for sharing the update with us.

[Bruce and Jenna]

Finished up today. We added tank straps, a plywood base, and a second tank washer. And several straps across the width to support the underbelly, since you can't install it as snug as the original. One band covers the access door for additional support.

Eight straps [roll of pipe strap] and 48" x 52" thin plywood [$10]




I cut open the old black tank today. Clean at the drain end with the tank washer. Filled with solids at the flange end with no washer. Which explains why my toilet clogged up weekly and water spurted up out of the valve. In spite of using the tank washer every time I dumped. And never leaving the black dump valve open. So I added a second washer directly in front of the tank inlet/flange.

Can't see the washer installed here. It has a garden hose fitting.


Ran it between the gray and black tanks.


Tada!


The entire job took my tech 10 hours. Figure I saved another two hours of work.

The work area

[rockintom]

Thanks Bruce. Interesting repair to say the least. I like the support of the plywood being applied to the whole underside (black and grey tank) but I wonder how long the plywood will last long term with moisture and all. Maybe I'm being over cautious. I'm surprised you didn't add a flusher to the grey too while you had it out! Take care and hope we see you and Jenna in OR this summer. rockybaby

[Bruce and Jenna]

Originally Posted by rockintom

Thanks Bruce. Interesting repair to say the least. I like the support of the plywood being applied to the whole underside (black and grey tank) but I wonder how long the plywood will last long term with moisture and all. Maybe I'm being over cautious. I'm surprised you didn't add a flusher to the grey too while you had it out! Take care and hope we see you and Jenna in OR this summer. rockybaby

Good point on moisture on the plywood. Shoulda coated it.

Good idea on a gray flusher too. But we managed to extract the black tank without moving the gray.