connecting bath to outside cast drain

[punch]

I need to connect a new drain from shower, bath and sink to original cast iron out - let.
There is no room around original to grip a rubber coller and cir clip. the inside diam of the cast pipe is just over 1 3/4 inch so i can insert new plastic one- and- three- quarter inch pipe inside the original ( 60 plus yrs ) orignial outlet. Is there a substance I can use to make this insert water tight ?
my supplier gave me the rubber fitting saying no material would be good enough to make water tight the connection, but when I got home I realised there's not enough room around the outside of the old fitting to get a fixing to,
advice would be appreciated

2 Photo's atached[/img]

 

[Nige F]

Just looked in your photo album - what a b`stard to connect to where does that old iron pipe go to ? is it possible to replace it - or maybe get @ it behind the wall it disappears into .

 

[Madrab]

looks like you may have a cast external waste with a lead insert there. The original waste pipes would have been lead and that has been cemented into the pipe. If you can't replace the cast then If you use a good waterproof adhesive, like evo wet grab or similar to cement the plastic into it, it should be ok. Just clean up the inside of that pipe first an roughen up the outside of the pipe you're putting in there and support it well at the exit point as the new pipe won't be that far into the cast iron.

 

[punch]

thanks nig f and mad rab, i've discovered a new possible problem in that the cast is rusty on inside and therefore is likely to leak into the stone wall eventually.So I've adapted my plastic insert to go all the way to the end of the cast. Ive sealed it by by running beads of silicone around the outside. left to cure for 24 hrs.
This has proven to be a tight fit inside the sat and works (hopefully as a lining. I've managed to get a good surface between the outside of the plastic one inch and the flange of the cast and saeld that with silicone too.
thanks for your help, i hope it will work.

 

[punch]

mad rab's query about lead insert :

I looked again and discovered that there is a smaller cast iron pipe inside the outer one, sealed with soft lead, i've scraped the lead awaya as much as possible to give space to mastic in my plastic insert. Again ghanks for your obvious long experience.