ᐅ How to Install a Toilet Waste Pipe Seal?

What is the best way to reinstall the seal on the toilet waste pipe inside the wall?

The pipe has a small collar at the front where the seal is supposed to slide back on, but I can’t get it back underneath. I’ve already tried heating the pipe with a heat gun, but it just won’t work.

Maybe you have some tips for me

Here are a few pictures of an old arch where the seal is still in place.

Hello Schwabe

The shown bend has a factory-installed lip seal that is normally not removable.
The new seal does not fit there.
You need to replace the entire bend.

Olli