I would prefer not to remove or damage the hub on the Wye. Before you begin check the hangers on the pipe above the section you intend to cut out. If there is any doubt whatsoever about whether it has adequate hangers take the time to install additional perforated strap hangers to insure it will not fall down when you cut the section out. (Dont take this caution lightly. Many stacks are self-supporting and if you cut a section out all that remains above it will immediately come crashing down with disastrous results.) The DWV grade copper at the top can easily be cut with a hacksaw or a sawzall with a metal cutting blade. Once you have the copper cut loose carefully try wiggling the cast iron back and forth a couple inches. Sometimes you can loosen the lead joint at the bottom in this fashion and the cast can be lifted out of the hub. You must work carefully to insure you are not causing strain on the other joints in the hub or it could result in a leak. If you cannot loosen the cast iron by wiggling it look for a cleanout at the base of the stack. (Code requires a cleanout at the base of the stack so you should have no problem locating one.) If it is an old cleanout the cap is most likely rusted in place and will require shattering it out. Usually a couple taps with a 3 pound hammer and cold chisel will shatter a cleanout cap enough that you can pry the pieces out of the hub without damaging the hub threads. Once you have the cleanout cap removed tie a string around the middle of a rag and wad the rag in the pipe through the cleanout to plug the soil pipe below the cleanout. The string will aid in removing the rag later. Cast iron is very strong but it is a very brittle metal. If you now hold a 3lb hammer tight against the cast iron pipe wall on one side and hit the pipe on the opposite side with a second 3lb hammer the cast iron will shatter. Break the cast iron out in this manner until it is only about 3 to 4" above the hub. You can now use the 3lb hammer and a cold chisel and strike the outside of the pipe forcing it inward to clean the remaining pipe out of the old lead/oakum joint in the hub. (The wad of rags we put in the cleanout is to catch any shards of cast iron that may fall down the pipe during the breakout.) Next use an electric drill with a fairly large bit (3/8") and drill two or three holes close together straight down into the lead. The idea is to cut the lead and form a starting point to pry the lead out of the joint. I have an old automobile wheel wrench that I use to pry the lead inwards. Once you have the lead started it will pry out easy. With the lead removed you can then use a medium sized flat screw driver to pry the old oakum out of the hub and clean the inside of the hub with a wire brush to remove any loose oakum. Reach down the inside of the pipe and remove any shards of cast iron that may have fallen down on the wad of rags. The inside diameter of a hub is generally much larger than the outside diameter of your new PVC pipe. I begin by setting a PVC coupling in the hub and pack it in place with new oakum until the depth of the hub is about 1/2 to 3/4 full of tightly packed oakum. I then fill the remainder of the hub with "Plumbers Epoxy" in the same manner as they formerly filled it with lead. Now measure the distance from the stop ring inside the PVC coupling to the bottom edge of the copper on top and cut a piece of PVC pipe about ¼" shorter. Slide a Fernco coupling on one end of your PVC pipe so it is completely on the pipe. (This will be the top end of the pipe.) On the opposite end of the PVC clean the pipe with PVC solvent/cleaner and apply PVC glue, then set the PVC pipe into the coupling in the hub. Align the top of the PVC with the copper and slide the Fernco upwards until it is centered over the joint and tighten the Fernco in place. Reach in the cleanout and make sure there are no remaining shards of cast iron on top of the rags. Once you are sure you can pull the string to remove the rags. Clean the threads of the cleanout with a wire brush and install a threaded PVC cleanout cap in the cleanout. (It is best to apply some Teflon thread dope to the cleanout cap before threading it in. This not only will insure a tight seal, it will make it much easer to get the cleanout cap out in future.)

From the description it is obvious that the pump outlet port has a female thread. I don't recall ever seeing a Fernco that could clamp on a female port and in my experience I have never found an epoxy that would reliably connect PVC to cast iron, especially if you throw vibration into the mix. The simple solution is to use an NPT thread tap and re-cut the female thread in the pump body, then you can apply some pipe dope to a male thread adapter and screw it into the pump body with ease. PVC does not hold up well to high vibration applications so to preclude future problems the pump should be firmly secured in place and if vibration is still a problem you should install a vibration dampening fitting on the line.

ThatÂs a good first posting, RH. I think you are a smart inquirer. Not that it matters. But, hereÂs a reply. Your query, "How long do these iron pipes last," is a great new question. The answer is, it depends. Aw Shucks. You see, if there are no extenuating circumstances, cast iron pipes are about as good as it gets. Of course, that is for old installations, such as yours. You can hardly beat PVC for new work. That said, if you have CI and it is properly installed, it will outlive you. I had a bad experience in a rental house. The idiots (sorry, they arenÂt that clever) installed CI piping when the sewers came thru after septic systems were the norm. It would have been just fine, except that the DIYers were not up to the task. They installed the new lines with a reverse slope. That is, instead of having a natural drainage slope of ¼" per foot, they installed the new pipes so that there was a small negative slope; but altogether it was a total fall. That is, the 4-inch pipes were fully adequate to take the flow, but the negative slope meant that there was a dip in the run that always was wetted with sewage. This failed, as luck would have it, years later when I became the owner. The CI pipe (No-Hub) which is a different recipe than the older version, was eaten-thru, so that is eventually formed a leak. The lower surfaces were rotted away and the leaks were evident as thin skin on the bottom-most outside diameter. This could easily occur, unseen, underground. CI pipe is a premium product. If you have it, it should last a "lifetime." Whatever that means. But I canÂt help thinking PVC is a superior product. I have also used ABS. It, too, is a great material for the purpose. It is much lighter in weight, but very durable. I would like to see it become the standard. Pinoke

You need to be more specific about what drain pipes are being replaced. Most folks don't dig up/demo the slab just to install new under-slab drain pipes unless they are filled with roots and dirt. If you are replacing the small drain pipes connected to the sinks and other fixtures, then PVC is a much better choice. Horizontal runs of small diameter (2", etc.) iron pipe builds up crud in the bottom and gets very rough, and then eventually rusts through because the iron pipe is often almost empty, wet and exposed to air. PVC tolerates that exposure much better. If you want really durable PVC you could specify stronger schedule 80 pipe, but I have never seen that used for DWV. The main soil stack may also be iron pipe, but usually a thinner iron pipe to keep down the weight. This means it sometimes rusts through faster, and its always a PIA to run because of the weight. For water supply lines in the house I would recommend using PEX for the new lines. It is cheaper than copper, and overall very easy to work with, which reduces the installation cost. It also tolerates freezing better, if that is a concern. Bruce