Re-working elderly plastic basin drain

[Rob Graham]

I can well bet this question has been asked several times before but the problem is finding the right words for a search.

I've had to replace the basin in my shower room. It came to me second hand 30 yeas ago and might even had a tiny crack then but something has triggered a significant crack recently.

As is the way of these things it takes as much effort getting the old one out as getting the new one in :>(

Anyway I've now got to re-work the plastic drain.

My problem is that I used a glue type pipe for the old one, and is 34.6mm od, and the only pipe I have anywhere near that is 36.4mm od with a 2mm wall. I do have access back to the 100mm drain stack where there is a push fit onto a 34.6mm diameter spigot.

I could redo the run quite easily, but I don't know what to buy - can someone give me guidance please.

Many thanks

[The Natural Philosopher]

Don't f*ck around, get a new adapter to the 100mm and replace the whole run with modern..

[John Rumm]

Quite often more - especially if tiled and sealed into place.

Solvent weld is typically a couple of mm larger in diameter than the nominal size so 1.25" / 32mm usually comes up around the 34mmin solvent weld. 36.4 sounds a bit large though...

By modern solvent weld fittings and pipe for all the new stuff, and join to the old using a "universal" compression type fitting.

[harry]

You will find that if you use compression fittings, they fit all the variants of waste pipe. More expensive and bulky but can be dismantled if neccessary in the future.

EG