Advice on unclogging cast iron P trap and/or joining it to PVC (pics included).

[tireshark]

Our shower drain backed up at our rent house... snaking it down the tub didnt work.

i removed the tub overflow pipe from the P trap (it seemed to be just sitting in the p trap, because it pretty much just lifted out... not sure if that's normal):

and the cast iron P trap is backed up with water. This is a picture of the whole system... the toilet drains fine:

I was planning on cutting it out and replacing with a PVC p trap... but i think i was having a blonde moment... why not try to snake the clog out from down at the p trap... duh.

So... that's what im going to try to do now... crawl back under and see if i can unclog it that way.

Any thoughts on anything? I assume that the best thing to do would be to replace it with pvc... but if i can get it unclogged i may just do that for now. Im already gonna have to replace the tub drain/pipe assembly because it was leaking and old/broken (the crossbars broke off the drain, so i imagine its gonna be a pain to remove).

If i replaced the cast iron, i thought i would cut through the 2" cast iron pipe about 6" before it hits the big 4" drain, and use a fernco coupler to join a 2" PVC to it... would that be an appropriate method?

 

[johnjh2o]

That will work but don't use a fernco coupling use a banded coupling.
http://www.fernco.com/plumbing/shielded-couplings/proflex-couplings
John

 

[tireshark]

thanks john.

wow ok i had another duh moment... i completely forgot that a p trap is SUPPOSED to have water in it like that. i went back and looked at the tub drain pipe that i had tossed aside when i removed it (the one i am holding in the first pic)... sure enough it was completely blocked. a bottle cap had gotten down the drain (because the crossbars are gone on it) and it had wedged in that pipe with a bunch of hair.

im want to replace the tub drain assembly with PVC (or steel if i have to) down to the cast iron ptrap if i can.

so here's my question now... the pipe im holding is galvanized steel, with what looks like a cast iron end threaded on to it. how is the bottom of that pipe supposed to attach to the ptrap? because it was previously just sitting in the ptrap (no idea if the water had been spilling out or not)... all i had to do was lift it a few inches and it came out.

i hand placed all the pipes back like they were to see if the water would drain out properly, and all the water spilled out at the ptrap... so that makes me wonder if that is what it has been doing for a while. shouldn't it have been sealed (or something) to the ptrap for it to flush the water out properly? i dont know how cast iron fittings like that work.

will i be able to run PVC (or galv steel) into that cast iron ptrap somehow?

thanks for your help!!

 

[johnjh2o]

At this point I would replace the line back to the main line with PVC including a new PVC trap. Cut the cast iron off close to the main line leaving enough to connect your banded coupling to.

John

 

[tireshark]

yeah you're right. that probably wont be much more of a hassle than trying to get pvc/steel back in the p trap, and it's what needs to be done.

out of curiosity, how do cast iron fitting like that join? was it wrong to just be sitting down in the ptrap?

 

[johnjh2o]

Cast iron joints like you had a calked with oakum (a rope like fiber) then molten lead in poured into the joint.

John

 

[tireshark]

Thx john.

Anyone got any tips on removing the tub drain, if the crossbars are broke? I got something wedged down in it pretty tight, but couldnt get it to twist loose. I think i might have to cut it out somehow. That dumb thing is probably gonna be harder to remove than cutting the CI pipe out.

 

[johnjh2o]

If you can get at it from under the tub you can cut it out. There should be a rubber gasket between the tub shoe and the tub. Try to get your saw blade in between the gasket and the tub shoe. That way the gasket will help protect the tub from being damaged.

John

 

[tireshark]

I ended up doing what this guy did:

http://www.hammerzone.com/archives/plumbing/bathtub/drain2/replace.htm

Except i used one of those little hand-held oscillating cutters. Made some cuts in the lip down to the tub, and pried it up with a screwdriver... eventually the pieces of lip snapped off, and it eventually got small enough to fall through the hole in the tub.

Got everything back together, and it all seems to be working ok.

Was a bit of a pain in the rear, but it saved my parents some money... and now i know how to do something new, haha.

Thx again for your input, john.

 

[johnjh2o]

Looks great. Glad to see you used a banded coupling.

John

 

[IFIXH20]

You might want to add support straping just pass your trap.