How to change waste pipe fitting with a small amount of male pipe to work with?

[Derek JJ]

I'm adding a 4th bathroom to my home and need to update the waste pipe going to the septic tank from 3" to 4". The pipe coming out of the foundation immediately transitions from 4" to 3" leaving < 1" of pipe between the foundation and the clean out fitting.

What would be the best way to cut off the 3" clean out so I can attach a 4" clean out fitting with such little room? How much 4" pipe do I need to insert into a 4" fitting?

I have a farmers porch right outside that pipe, so extending it from the outside would be painful.

Options
1. Try to get the old fitting off, looks hard to do.
2. Using a 4" inside coupler? Would the little lip will block the sewage flow? https://www.pvcfittingsonline.com/4-schedule-40-pvc-pipe-inside-connector-s0302-40.html
3. Other ideas?

 

[Terry]

Cutting the fitting even with the end of the pipe, and then carefully with a handsaw, cut at least two slices of the fitting left on the pipe and taking a flat blade screw driver and a hammer, tap off the hub by splitting it from the pipe.
The fitting can be spread apart, breaking the connection it has to the pipe.

4" inserts half the pipe size, so 2"

 

[Sponsor]

 

[Tuttles Revenge]

I've removed ABS fittings using heat.. not sure that would help with PVC.

Is the WYE a 4x3 so that you have 4" at the cleanout and 3" at the branch at the top? If so you could ream out the cleanout and add a connection there?

 

[Derek JJ]

Cutting the fitting even with the end of the pipe, and then carefully with a handsaw, cut at least two slices of the fitting left on the pipe and taking a flat blade screw driver and a hammer, tap off the hub by splitting it from the pipe.
The fitting can be spread apart, breaking the connection it has to the pipe.

4" inserts half the pipe size, so 2"

Cutting the fitting even with the end of the pipe, and then carefully with a handsaw, cut at least two slices of the fitting left on the pipe and taking a flat blade screw driver and a hammer, tap off the hub by splitting it from the pipe.
The fitting can be spread apart, breaking the connection it has to the pipe.

4" inserts half the pipe size, so 2"

Thanks Terry! The diagram helps a lot. Since you have done it before, would the screwdriver splitting be going down the pipe or parallel to the pipe or a little of what ever works? Thanks again.

 

[Reach4]

Thanks Terry! The diagram helps a lot. Since you have done it before, would the screwdriver splitting be going down the pipe or parallel to the pipe or a little of what ever works? Thanks again.

I would think perpendicular for prying or tangential for tapping.