fill gap between 4" pipe and basin

[Qwertyjjj]

I need to fill a gap between a 4" inlet pipe and sewage basin.

I don't think I can retrofit a uniseal as it has to go on the outside and that would involve breaking concrete and redoing the pipes.
I was thinking of opening the lid, spraying in foam in between the pipe and the hole to fill and flatten the gap, cutting it any excess foam on the inside of basin, then applying silicone all over it to seal.

...or plumbers epoxy?

 

[Reach4]

I would read up on 3M 5200 marine sealant. I have never used it.

 

[Sponsor]

 

[Cacher_Chick]

If you know what kind of basin it is or the actual hole diameter, you should find the proper replacement seal. If you don't get it properly fixed, it will burn the pump out.

 

[Qwertyjjj]

Why would it burn the pump out? It's the waste inlet to the basin? The pump works regardless of whether that is sealed or not.

Would epoxy fill the gap also?
It's a 4" waste pipe so the diameter of inlet hole to basin is slightly bigger than that. A 4" uniseal would do it but I can;t retrofit that now.

 

[Cacher_Chick]

Why would it burn the pump out? It's the waste inlet to the basin? The pump works regardless or what's happening there?

Would epoxy fill the gap also?
It's a 4" waste pipe so the diameter of inlet hole to basin is slightly bigger than that. A 4" uniseal would do it but I can;t retrofit that now.

During periods of rain the groundwater can leak into the basin, basically turning it into a sump pit and causing the pump to cycle over and over. We have had to dig out a number of these to fix them.

 

[Qwertyjjj]

Aha, I see what you mean now.
Do you think epoxy will work as a seal though? I'm still not keen on digging it up if I can seal from the inside using filler foam and then epoxy between the PVC pipe and basin.

 

[Cacher_Chick]

There are things you can try, but fixing it right the first time will be the best way to achieve good results.

I use the 3-M 5200 on boats. It works if the joint is stable and the bead is limited to about 1/8th inch or less. The problem in your case is that the seal really needs to be made on the outside of the basin, and if you were going to do that, you might just as well fix it right.