We are doing renovations on a 40 year old hospital built by Japanese on Pohnpei. We pulled the water closets out and exposed the closet flange. The drain is cast iron with oakum and lead joint. Pipe is very brittle and we I am scared to drill holes around it because it may break. Its already starting to break when we first tried to drill holes. Is there any easier way to remove this oakum lead joint without breaking the pipe?

I cut my plumbing teeth on lead and oakum joints,
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. Good luck, Tom