Another basement tub drain question

[fattireb]

I was able to finally remove my tub and now am in the process of replacing the drain assembly for my new tub. Few questions of course....
Here is what the previous drain looked like. It has this exhaust thing sticking up to the left. anyone know what this is for and will I need to work the same type thing into my new assembly?
http://pics.bikerag.com/Uploads/data//500/IMG_6992.JPG

Also the old assembly pretty much slide out of the buried drain (wasn't screwed in). I figure its gravity fed? Does the new assembly need to screw in to be leak proof? Can I connect PVC to the brass thats there?
http://pics.bikerag.com/Uploads/data//500/IMG_6993.JPG

Last one....for now :o - When I removed the old assembly the drain foot has water in it. When I ran my upstairs shower it filled the hole in the floor. Anything to worry about?

Thanks in advance!

[jadnashua]

Yes, you have problems. While there should be water in the p-trap, it shouldn't back up and flood things. I think they intended that vertical pipe to be a vent, but since it's not in the right place or connected to the rest of the vent system, it does nothing. Sounds like you have a partial blockage in your drain. If the water didn't come out the top, then you may also have a hole in the trap. You may be tearing more out to be able to replace the worn out sections. See what the pros have to say...I've been known to be wrong!

[Gary Swart]

While it is true that this forum is to provide assistance to a DIYer, sometimes the best advice we can offer is to hire a professional plumber. There a many ways to do this job, but most of them are wrong. The last thing you want is to find that after much work and expense what you have done won't pass inspection and has to be torn out and redone.