sealing tub outlet pipe?

[Kman]

OK....pulled the old CI tub.

Messing with the old bathtub "T" fitting (that connects overflow pipe and main tub drain with outlet drain pipe) (is there a proper name for this T?) I notice it's loose...the whole pipe is loose...

...dig down in the blocked-out area of slab, and find that pipe is 1.5" galv steel, rusted out...dig it up, unthread it, and replace with 1.5" ABS pipe (into CI p-trap)...which ABS has 1.5" pipe thread fittings top and bottom...top one I ended up having to shorten the thread length (it's still adequate) and FILED a flat ring on the top where I cut off the threads...

Put new T fitting kit and non-CI tub in....

NOW the problem: I can't get the 1 3/8" outlet pipe from the T to the ABS fiiting to seal...it weaps water when I drain a full tub ....this joint should be water tite (constriction in drain line is a separate issue for me)

The plumbing compression coupling / nut I'm using is for 1.5" tube...is this my problem?

Is the flat ring for the ABS fitting incorrect and preventing the necessary distortion of the seal?

Are there some sort of super seals I can find to seal this joint?

Thanks for any advice...I need to move forward with this job...

[jimbo]

Any time you cut tapered pipe threads, you invite a leak. Not sure what type of fittings you are using. I would suggest that everything north of the cast iron be glued-up ABS.

[hj]

You are confusing us. A 1 3/8" drain would normally only come with a leg type tub, and if so, then you need a 1 1/2" x 1 3/8" adapter slip nut and washer. Tub drains do not connect with flat washers, so that might also be the problem.

[Kman]

You are confusing us. A 1 3/8" drain would normally only come with a leg type tub, and if so, then you need a 1 1/2" x 1 3/8" adapter slip nut and washer. Tub drains do not connect with flat washers, so that might also be the problem.

I was afraid my imprecise terminology would confuse the issues.

The new T-fitting kit from Home Depot is 1 1/2" on 2 input legs, but 1 3/8" on the outlet leg...guess they did that so it fits new and old plumbling installations...the kit came with worthless cast-zinc slip nuts, one of which broke when I hand tightened it...bought brass replacements...

I am using a 1 1/2" brass slip nut with thin metal washer (down to 1 3/8" ID) and a 1 1/2" x 1 3/8" washer.

Is this clearer?

"Any time you cut tapered pipe threads, you invite a leak."

But in this case, the threads don't have to seal - just allow the brass slip nut to tighten the washer to seal against the 1 3/8" tube...

[hj]

If you knew how old, and rare, a 1 3/8" pipe was, and they all went into a 1 1/2" pipe anyway, you would realize that there would be no reason for HD to offer that option.

[Kman]

If you knew how old, and rare, a 1 3/8" pipe was, and they all went into a 1 1/2" pipe anyway, you would realize that there would be no reason for HD to offer that option.

?? well Home Depot does...they stock a commercially-available kit...

...and my joint still leaks....

[hj]

Welll, if they do, and I will have to check it, that violates the prime directive of plumbing that you do not reduce the pipe size of a drain in the direction of the flow. But now we would have to see a picture of your connection to determine if we can tell why it leaks.