I've attached a picture of the drain pipe. The kitchen and bathroom sink and bathtub all lead into this pipe before the crack. The crack is about 4" long in a lead pipe (I believe) which is threaded into a cast iron T. The crack goes all the way to the cast iron T and I'm wondering if that would make it hard to patch? Another option would be to cut out the bad section of pipe and replace it? Any advice is much appreciated

Looks like galvanized pipe to me. Cut out and replace all accessible galvanized pipe with PVC pipe. Make connection to cast iron with gasket or soil seal. Galvanized is leaded into cast iron. Cut pipe 6" from joint, drill a number of small holes in lead around pipe until pipe is loosened and can be pulled out.

... Then, insert new section of pipe ( can be ABS, PVC ) , use 2 Fernco couplings to connect new and old. You will need 3"CI x 2" CI coupling for the Y side, and 2" x 2" for the pipe to pipe connection ( explanation: 3" CI so you can get it over the Hub ).

Both experts are correct. You have a galvanized pipe that's been caulked into a cast iron combination wye and eighth bend. What is it you wish to do? Replace the entire run of galvanized or cut out the old faulty galvanized and patch in a piece of plastic.
At any rate the very first thing you're going to hafta do is remove the lead and oakum joint. To remove a poured lead and oakum joint take a 3/8" drill bit and drill a few holes down past the lead and into the oakum.. Push a screwdriver under the lead ring and lever it up. Once it's free you can began to peel the lead ring out. Now pick out the oakum and you can pull the joint apart. Now tell me what is is you want to do. Regards, Tom

I'm not sure, but I think I see threads on that galv pipe?? I don't think this is a lead and okum joint,, if it is, its just plain wrong to lead galv into cast. I suggest trying to get all of the galv thread out of the threaded cast fitting, and then use a thread cleaning tool to get it real clean, then use a two inch pvc MIP adapter to thread into cast fitting, and glue joints from there. Or, just cut out the whole wye, and replace with pvc,, adapt the new pvc wye at both inlets with shielded rubber clamps(with short pieces of pvc coming out of pvc wye.

I agree with MGD77: The gal. pipe is screwed in, therefore, it is cast iron, tapped, fitting.

Is this post still open it was posted in August? Thanks.

Regards,
John

Lol, I got to learn to look closer at the post date. Thanks John. Lee.

Me Too! Tom