Leaking Tub Valve

[Marilyn]

We have a 1930s Am. Std. tub valve (separate hot and cold sides). A while ago we noticed a drip at the outside wall in the basement, under the tub. We believe that the problem is in the hot water supply side. We took apart both valves, replaced the washers (even though there was no drip at the spout), got rid of any calcification that we could see, repacked the stems and reinstalled. We still have the drip in the basement, although it has lessened. The escutcheons at the tile wall are off and we cannot see any leakage at the valve in the wall. Any suggestions as to how to proceed from the pros? Thanks for your help.

[jadnashua]

It could be numerous things: you could have a pinhole leak in one of the pipes, the trap could be shot, and probably other things as well. You may need to tear out some stuff to check further. If there is no drip from the spout, unless the pipe from the valves to the spout has problems, it is coming from somewhere else.

[Verdeboy]

Does it leak all the time or just when you are using it? If it leaks all the time, try to isolate the leak by turning off the hot water shutoff valve and see if it stops leaking. Look for the highest point that the water is coming from to determine the origin of the leak.

If it leaks worse after a bath, problem is likely to be in the drain or the overflow.

[Marilyn]

Thanks for your replies. The drip happens only when we open the hot water valve. We tried leaving water in the tub for a couple of hours to make sure it wasn't coming from the drain area. It stopped dripping a few minutes after we turned off the hot water.

The water supply lines to the tub appear to be in the plaster across the basement ceiling--disappear into the lath and plaster under the tub area (the water heater is in the basement).

Thank you

[Verdeboy]

The drip happens only when we open the hot water valve.

If you mean the hot water shutoff valve, then the leak must be somewhere between this shutoff valve and the hot water faucet stem. This means accessing that stretch of plumbing by whatever means is necessary.

If you mean the hot water valve stem, then just replace the valve stem and seat.