Replacing brass tub drain with PVC

[ChrisMDL]

Hey all,

Nothing but great things to say about the forum. Immense help. Hoping to tap your knowledge yet again.

I need to replace an old brass tub drain. As you can see in the pictures it's not serviceable. The drain then moves to the stack.

I don't think I want to mess with the joint between the brass and the cast iron.

Where should I cut the brass out and what can I replace this whole set up with (drain + overflow + p-trap )?

Also how can I make the connection from the cut off brass to the new PVC? Can I use a Fernco fitting on its side like that?

 

[Terry]

Fernco makes a shielded coupling that transistions between copper and plastic.
Normally I would place the p-trap below the tub waste and overflow. I don't know why they used a "running" trap on that. I would remove that.
You're best off to install a new plastic trap while replacing the W&O.
Install the new tub drain, and then the last fitting can be the p-trap.

 

[Sponsor]

 

[Cacher_Chick]

My concern would be the vent, as there does not appear to be one.

 

[Terry]

My concern would be the vent, as there does not appear to be one.

Good catch. I notice there is a Studor Vent below that. This home is so old that whoever plumbed it at that time must not have been aware of vents and what they do. Adding a vent on the tub trap arm would be good.

 

[ChrisMDL]

As you can see the drain goes into the main stack which has its wet vent that goes up through the roof right there. The studor vent is for a utility sink that's further from the stack/vent.

So I'll cut the copper then close to the old trap and replace everything. Thanks for the help fellas!

 

[hj]

WHY isn't the brass drain "serviceable"? Other than the drain line being installed by someone who did not know anything about plumbing, there should be no problem with the tub drain itself.

 

[ChrisMDL]

Well it has accumulated 60 years of hair, dirt, and grime and drains slooow. I would like to add a cleanout to some part of my new setup as well for that reason.

 

[Cacher_Chick]

Wet venting between floors is not permitted, and if it were, the allowed trap to vent distance would be exceeded.

 

[hj]

Snaking the drain would improve the flow, but whoever installed the trap wanted to make it difficult to do that, however it can be done. Whoever installed it knew little about plumbing so why would he know ANYTHING about vents?