leaking tdub spout

[meoli5]

My problem-I had a tub spout leaking cold water. I replace the seats and valve stems in the hot and cold sides and in the diverter and I still have the leak-any suggestions?

[LazyPup]

I would suspect you have one of two problems. The most likely cause of the leak is a defective valve seat.

Most shower mixers that have stem washers also have replacable valve seats.

Begin by removing the stem, then depending on the diameter of the stem you may be able to feel the surface of the seat with your finger. If you cannot feel the surface you will have to pull the stem for inspection.

The inside opening of vavle seats are machined with a recessed square or hexagonal opening to permit unscrewing with a valve seat wrench.

You can buy an inexpensive valve seat wrench at any hardware or home supply plumbing department.

There are two common styles of valve seat wrenches. One is a straight piece of metal about 6 inches long with a tapered square on one end and a tapered hexagonal surface on the other. The more common style is L-shaped with the hex on one end and the tapered square on the other. ( I personally prefer the straight type, as the L-shaped wrench will hit the tub spout and require resetting the wrench two or three times before the seat is out. The straight line design is fitted into the seat, then turned with a small adjustable wrench. It is a bit easier to restart the seats with the straight line type, but either wrench will work okay.)

Begin by pulling the valve stem, then using a flashlight look at the interior opening of the seat to determine if your seats have a square or hexagonal opening. Insert the appropriate end of the valve seat wrench and unscrew the seat.

Once the seat is out examine the face and you will probably see one or more large pits in the surface that is causing your leak. Once the seat is out you can take it to your local hardware and get a replacement seat. Normally you can assume that if one seat is bad the other two are probably are also getting bad. Best bet it to change all three at the same time.

Here is a tip. Normally the diverter seat is the same as a faucett seat. If so, you can reassemble the faucett seats and turn the water on again. It will still leak, but at least you have use of the water while you go to to store to get the new seats.

Once you have the new seats, remove the old seats, wrap some teflon tape on the threads of the new seats and screw them into place.

Also, before you reinstall the stems, check the washers again. Often when people change stem washers they forget to turn the stem to the fully open position before installing the stem. If a stem is fitted with a new washer, then installed with the stem in the closed (water off) position when the stem is tightened it forces the new washer against the seat to the same position of the defective washer, thereby immediately distorting the new washer.

[HayZee518]

Lazypup - what do you think of the idea to put some never-seez on the new brass threads of the new seats. Then if you ever have to replace them you won't have to fight city hall to get them out.

[LazyPup]

Never seize would probably not hold up as the threads are constantly exposed to water under pressure. On the other hand, contrary to the belief of most ppl, teflon tape is not a thread sealer, it is a thread lubricant. There is a thicker type of teflon tape that is approved as a thread sealer, but even then only if three layers is applied.

[HayZee518]

I know that - hey add me to your yahoo messenger link ok?

[mrcaptainbob]

WHAT?????!!!!!!!![:0][:0] Teflon tape isn't a thread sealer? Well, THAT explains why I had to put about eight wraps of it, as well as coat the first four threads with teflon dope and STILL reef on the fittings to stop the leaks!! What tape would I use for the threads in a water system with 40/60 psi? And thanks for the new info..(new to me!)

[LazyPup]

The 1/2 wide flimsy white teflon tape that is commonly found in hardware stores is certified as a thread lubricant, and is approved as a thread sealant in limited applications. Primarily for finely threaded fittings of 3/8 of an inch or less in diameter.

In the trade we use a variation of teflon tape that is 3 times as thick and packed in 3/4 inch wide x 520 inch rolls. Per the manufacturers specifications and MILSPEC regultions it is certified as a thread sealant when 3 or more wraps is applied.

Recently we have begun to see a heavier variety of teflon tape showing up in the hardware stores. The heavier varieties are color coded. The pink being about twice as thick and the yellow is 3 times as thick, or approximately equal to the commercial type used by plumbers.

While the actual composition of the material remains the same, there is a heavier guage of teflon tape that is commonly sold as High Density teflon or "GAS" tape. You would have to check with your local code authority before using the GAS tape on water lines. Although it is just a thicker variety of the same material, some inpectors will not pass it because the package does not list it as suitable for use on water lines. By Contrast, my local inspector prefers to see it.

There is also a proper method of installing teflon tape. Begin with a short tail of the tape coming off the top of the roll. Hold the roll on the left side of the pipe and hold the end of the tape on the underside of the pipe to be threaded, then begin wrapping in a clockwise rotation. Keep a continuous back pressure on the roll to slightly stretch the tape as you wrap. This figure 8 method will insure proper tension so the tape is drawn into the threads of the pipe to effect a good seal. (see photo)

Teflon tape is best suited for fittings that you anticipate will require periodic maintenance such as when attaching a shower arm. For permanet fittings the preferred method is to use pipe dope.

A word of caution when selecting pipe dope. READ the Label and make sure it is listed for the type of service you intend to use it on. Some dopes are only listed for water or gas, while others are listed for oils, natural gas, propane, high and low pressure air, etc etc.

My personal preference is a dope called "Rector Seal". It is a non-hardening dope that is listed for potable water, steam, natural gas, propane, gasoline, high and low pressure air, inert gases and many more applications.

[mrcaptainbob]

That picture shows pretty much what I usually do. Except I was always using about three wraps of the 1/2" stuff on the blue spools. Since there were a few leaks on a couple of the threaded areas, I was sooo unnerved by having to take it all apart to get to them, that I wrapped it following the threads on the pipea! Now I usually do about 6 or 7 wraps of that stuff. I'll be looking for that heavier stuff from now on....Thanks for the guidance and helpful pics.

[HayZee518]

Rector-seal is the ONLY way to go! I've tried others and always come back to rector-seal
Teflon's ok if you always have to take apart and re-assemble a joint as in an industrial application. Rector-seal - apply it and leave it alone!

[LazyPup]

Often rector seal is difficult to find in hardware or homesupply stores. If you can't find it there contact any local plumbing supply and most heating supply stores and they will have it. It is almost a standby item in the plumbing trade.