Replacing old cast Iron sewer pipe with new

I am having problems with a clogged sewer line. I have had it cleaned out twice with in the last 2 month by 2 different pro. plumbers. On both occations, the drains worked perfectly when the plumbers left. Well it's clogged again. I'm to the point of replacing that section of cast iron pipe. It's about a 50' run and about 3.5' deep. My question is, would this be addviseable and step by step of how would I go about it? I'm 56 years old,retired and have more time than money. Thanks for any help.

First thing I'd do is have a camera inspection of the whole line. You want to make sure how much needs to be replace or if a less drastic repair would be enough. Replacing sewer line is not a job I would recommend for DIY. Sewers are usually quite deep so there is a real danger of cave-in not to mention the shear amount of digging involved which, even in ideal soil and conditions, can be exhausting. Then there is the need to keep the proper slope in the new line. If the line settles after it is covered, you're almost back to square one. I'm like you, more time than money, but I've got a few years head start on you, and I'm finally learning that my mind can conjure up jobs that my body can't cash.

After you have it inspected, have a sewer cleaner run a chain knocker through the line to descale the cast iron. I had a home owner with a 150 foot run of 4" cast. The village dug up the parkway where the cast finally went into a 6" clay sewer. The village televised the line told him the reason he was clogging was the cast iron was way to rough on the inside due to corrosion. I talked him into letting me run a chain knocker through and re-televise the line If he or the village was not satisfied I wont charge him. They both where shocked, the line looked like a brand new pipe when i was done.