On my last camping trip, noticed a small wet spot under the trailer as we were about to pull out and leave. Turns out- a hairline crack in the grey tank ABS pipe leaving the grey tank.The crack has gotten large enough that I believe I need to cut the pipe and try to patch with a rubber coupling, as opposed to some sort of jb weld solution. Question is- how to approach that? I'd like to cut the pipe flush with the collar, and have a rubber coupling (a Fernco coupling perhaps) go over the collar on one end, and then into the 1.5" abs pipe on the other end, but- I'm not sure what size the rubber coupling needs to be to fit over the collar...if it's even made in that size.Or- other suggestions on how I should approach a fix?

first question. Why did it crack? if it is a stress crack you want to make sure the repair fixes that. Next, not clear from the picture, but is the fitting a rubber donut of some sort into the tank? If so that would make removal and repair easier

Trailer is a KZ Coyote, 10 years old. I think over time, the bumpy roads have just done it in. The last trip we took, while the highway was paved, there were a lot of dips in the road, which I suspect pushed it over the edge.I believe the "collar" right after the pipe to be plastic, but to your point- I just don't know what pieces have been spin welded into the grey tank. To me, the "collar" almost seems like part of the 1.5" abs pipe, but- if that's "glued" onto the other pieces at the right, then probably not getting it off. Hence, my thought of cutting if flush at the collar, and then use some sort of rubber coupling over the collar

My first inclination would be to use Plasti-Mend ABS solvent to seal the leak. Although that crack is a concern.Yes I could see using a step down coupling to attach that first step to the pipe after cutting it back. Could be hard to get the size right depending on that fitting. If something fits then it should be a slam dunk.

If you do just use a solvent to seal the crack, first drill small holes at the ends of the crack to keep it from growing.

I would try your suggestion for a Fernco coupling. They come in hundreds of sizes and styles.You might also look at how you can better support the pipe to reduce movement.

Grey tank ABS pipe leak | Good Sam Community

ssthrd
Explorer
Dec 06, 2021
Home Depot has "Mission" couplings that have rubber bushings made to reduce one end. you will need to get an accurate OD on the large end to know what size coupling to get.

They might also have a slip on ABS reducer to go from 3" or whatever size you get when you measure the OD to 1 ½" at the small end. They just glue on. you would need some slack on the 1 ½" to get it together. Short of replacing the whole pipe, the second option would be my choice.

I wonder if the tank looks like the pipe...... just saying.

EDIT:
My bad. You would need either an eccentric coupling to fix as is, or have the ability to raise the 1½" to use a concentric coupling. Second option would leave ¾" of grey water in the tank.
StarkNaked
Explorer II
Dec 06, 2021
I would try your suggestion for a Fernco coupling. They come in hundreds of sizes and styles.

You might also look at how you can better support the pipe to reduce movement.
Darklock
Explorer
Dec 05, 2021
If you do just use a solvent to seal the crack, first drill small holes at the ends of the crack to keep it from growing.
time2roll
Nomad
Dec 05, 2021
My first inclination would be to use Plasti-Mend ABS solvent to seal the leak. Although that crack is a concern.

Yes I could see using a step down coupling to attach that first step to the pipe after cutting it back. Could be hard to get the size right depending on that fitting. If something fits then it should be a slam dunk.
frisco_dave
Explorer
Dec 05, 2021
Trailer is a KZ Coyote, 10 years old. I think over time, the bumpy roads have just done it in. The last trip we took, while the highway was paved, there were a lot of dips in the road, which I suspect pushed it over the edge.

I believe the "collar" right after the pipe to be plastic, but to your point- I just don't know what pieces have been spin welded into the grey tank. To me, the "collar" almost seems like part of the 1.5" abs pipe, but- if that's "glued" onto the other pieces at the right, then probably not getting it off. Hence, my thought of cutting if flush at the collar, and then use some sort of rubber coupling over the collar
ktmrfs
Explorer II
Dec 05, 2021
first question. Why did it crack? if it is a stress crack you want to make sure the repair fixes that.
Next, not clear from the picture, but is the fitting a rubber donut of some sort into the tank? If so that would make removal and repair easier

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Grey tank ABS pipe leak

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