This Old House plumbing and heating expert Richard Trethewey shows how to replace an old bathtub drum trap with a new PVC P-trap In this video, This Old House plumbing and heating expert Richard Trethewey shows how to replace an old bathtub drum trap with a new PVC P-trap. 1. Use reciprocating saw fitted with a metal-cutting blade to cut out the old iron drum trap; be careful when lowering the trap, it's filled with water. 2. Loosen the old threaded adapter that's attached to the existing drain line using two large pipe wrenches; use one wrench to hold the pipe, and the other to turn the adapter. 3. Once it's loose, remove the adapter with pliers. 4. Brush pipe dope onto the threads of a PVC male adapter, then wrap the threads with single-strand wicking to provide extra protection against water leaks. 5. Insert male adapter into the existing iron fitting, and tighten the adapter with pliers. 6. Apply pipe dope and wicking to the existing iron male fitting, then install a threaded PVC female adapter, tightening it with pliers.
7. Dry fit (no glue) the PVC P-trap and PVC pipes to ensure they fit together properly. 8. Measure last piece of PVC pipe, and cut it to size using a PVC cutter or hacksaw. 9. Use a pocketknife to scrape off any rough burrs from the just-cut end of the PVC pipe. 10. Dry fit together all the parts one final time, then use an indelible marker to draw alignment marks onto the pipes and fittings. 11. Disassemble the PVC pipes and fittings, then clean them with PVC primer. 12. Permanently glue together the pipes and fittings with PVC cement, making sure you line up the marks drawn earlier in Step 10. Last Updated: 26 July 2016 A clogged bathtub trap is a bigger problem to fix, but not impossible. Unfortunately, it does mean some extra work. Before you assume that it is the trap you want to make sure that you to check a couple of other things. Two common problems with bathtub drains are hair in the strainer and a stuck or broken pop-up assembly. See the articles 'Fixing Bathtub Drain Clogs' and 'Repairing Bathtub Drain Stoppers', for more information and instructions.
Bathtub drains have traps to keep sewer gas from getting into the house. For a bathtub that has a basement or crawl space below it you may be able to see it from below. When the house is built on a slab or for an upstairs bathtub, there should be an access panel on the opposite side of the wall. This might be in a closet or bedroom wall in the room that is on the other side of the drain end of the tub. Unfortunately, this trap differs from the ones under your sinks. Usually the fitting are glued or soldered together and do not come apart. For a clog in the trap you will have to run a snake through it. I do not recommend drain cleaners. Very bad chemicals that are not environmentally friendly is one reason. The other is that they don't work that well. Some bathroom traps have a clean out plug on them. This a nice feature and makes cleaning out the trap much easier. The clean out plug will be located at the bottom of the trap. Before you remove the plug you want to have a pail underneath that will catch the water.
If the bathtub is full of water, it is not a good idea to use the clean out plug. All of the water in the tub my come gushing out. With a full bathtub, you want to snake out the trap, see below. The bathtub drain is usually in close proximity to the larger main line that the toilet is hooked to. This means that you don't need a long snake. Generally less than 25' in length. It should be a small snake, one that is suitable for a sink line. Do Not try to snake a bathtub drain through the drain in the bottom of the tub. There is no way to control which way the snake will go. In addition, the strainer opening is too restrictive to get a snake through, it will bind the snake and may cause it to twist. Do Not try to snake a bath tub drain without removing the pop-up assembly. The snake will catch on the assembly and may ruin the linkage, the snake or both. Take off the cover for the overflow and remove the linkage and plunger for the stopper. This is normally the spot the has the control for the drain, either a lever or a dial that causes the drain to operate.
Run the snake down through the opening. The toughest part will getting through the trap. Apply pressure and turn the snake until it twists through the trap. Try to judge the distance you need to go to get to the stack behind the toilet. Run the snake through a couple of times. If the tub has water in it, the draining of said water is a sure sign you have been successful. If you do not have water in the tub, try running water into the tub and see if it is draining. If so, put the pop-up assembly back in and fill the tub part way. Let it drain out with the water running. If you have snaked the drain and made sure the 'Bathtub Linkage' is working correcly, then you may still have some issues at the strainer, see the article 'Bathtub Drain Clogged' for information and instructions.Great this clogged bathtub drain problem is solved.The curvy pipe under your sink is called the P-trap. It’s designed to prevent noxious gases from backing up through a drain by holding water in the bend, sealing the trap.
Also, its shape makes it possible to recover dropped items (like wedding rings) that may otherwise be lost in the drain. Hair, accumulated soap, and dirt can all clog the drain over time, but this can be easily fixed. It is relatively simple to remove and replace a leaky or clogged P-trap without spending the money on a plumber. Before you start, put on your gloves to protect your hands from any contaminated or decayed material that you might come in contact with during the process. Also, wear a face mask to keep yourself from inhaling any mold spores or other airborne contaminants that might be present in the trap Next, you need to make sure the water is turned off completely. Turn off the taps, but also close the valves under the sink. You don’t want someone to turn on the water if you walk away from the job for a moment. Test that the water is completely off by turning the tap on once more. Then, place the bucket below the drain before pulling out the P-trap to capture any fluid or objects from spill out when you remove it.
Use a pair of channel-lock pliers to loosen the nuts at the top and bottom of the P-trap. If they’re tight, you may have to use some force, but be gentle so you don’t crack the tail piece coming from the sink, the trap itself, or the drain stub coming from the wall. After loosening the nuts, unscrew them the rest of the way with your hand. Once the nuts are off, carefully remove the P-trap, ensuring that the contents do not fall anywhere other than the bucket placed under it. Empty out all the contents of the trap. Expect all kinds of debris such as hair, slime, and dirt. This is where the gloves come in handy. If you are looking for an object that could have fallen into the drain, you should be able to spot it when you empty the contents. If you don’t find it, you might need to fully clean out the P-trap with hot water and soap. Use a bottle brush to scrub out the inside, as this will get rid of all the extra buildup in the drain and will help prevent further blockages.
This should all be more than enough to solve the problem of unclogging the drain, but if the trap is broken or worn, you should replace it at this time. If the trap was leaky or broken, or if it’s an old one made of chrome, you want to replace it with ABS or PVC plastic. Chrome traps may look classy, but they corrode quickly. However, if it’s an old brass one, you probably don’t need to replace it. To ensure you get the correct size P-trap for a replacement, take the old one with you to the hardware store. A plastic P-trap comes with a complete package, that is, nuts and gaskets included. Now, install the new P-trap. It should easily fit into place, and the threaded ends should be wrapped with Teflon tape. When the P-trap is placed in its right position, slide the nut over the gasket and screw it down on the sink’s tailpiece. Then, on the trap’s tailpiece, screw the nut and gasket onto the drain stub. Use the wrench or channel-locks to turn the nuts just past hand tight.