Trouble snaking tub drain

[LarryFahnoe]

Main problem: a bathtub in a 1920s house is draining very slowly. P-trap is brass connected to a galvanized drain line. Furnace ducts block access to the drain line & even if I could access the area, I'm doubtful that I could get the P-trap off. Since everything is old, I'd rather not create bigger problems by trying to open it up. P-trap has a drain plug in the bottom of the P but it looks like it is a glav. plug and is stuck tight, so it would appear my only option is to come in from the tub.

Thinking it might be simply hair I tried a 2ft hair snake but it didn't bring anything up. Next I took off the overflow/drain handle cover and removed the drain stopper from the tail pipe. I've got a Spartan 81 cable machine so I tried with a 5/16" cable and my smallest blade (3/4", shaped like a "C") but could not get it past the P-trap. So I bought a 15ft 1/4" cable with just an open hook end (corkscrew) and tried feeding it with just the offset tubing style handle that came with it but could not get it past the P-trap. I put a slight bend into the cable at the base of the hook and tried again, no luck. I then put the 1/4" cable onto the Spartan but found that the small cable wanted to kink up in the 1-1/2" tail pipe so I took a length of flex conduit (BX?) with an ID of about 5/8" to act as a support for the cable and fed it down to the top of the P-trap. Still no luck getting the cable past the P-trap though. Next I tried a steel electricians fish tape just to see if I could push it through the P-trap. Slow going but it feels like it is getting through. Based upon reading other comments, it looks like a 1/4" cable should get through a 1-1/2" P-trap, but I've never tried before.

I'm guessing that part of the problem is my lack of skill & experience with drain cleaning. I've tried feeding the cable using fairly constant pressure and also sort of pulsing it. I have also run the machine constantly as well as pulsing it. I'm handling the cable with leather gloves & that's allowed sufficient force to be applied other times I've had to clean drains. The cable is loaded correctly and the drum is running in the forward direction. My sense is that the cable is just not wanting to navigate the 1st bend in the P-trap. Is it just a matter of patience and luck/chance to get the cable to feed into and through a P-trap???

I'll be grateful for any advice or words of wisdom.

--Larry

 

[LarryFahnoe]

Well after my efforts to snake the drain failed I spent some more time with a stiff steel fish tape with a tiny loop at the end (lest a hook get caught on the lip of a fitting and cause yet more trouble). The fish tape would make it past the P-trap and then stop after a couple of feet but it was difficult for me to determine if this was due to hitting an obstacle or just the small tape in the relatively large pipe being obnoxious. After this the tub was not draining at all, so maybe I was poking on the clog & making it worse, I don't know.

I left it for a week and came back to the same inch or so of water in the tub so I started with the shop vac and used a tube to get down the tail pipe to the P-trap level. I cleaned out all the water that I could with the vac, then switched tactics. I plugged the drain and then put a funnel on the tube down the tail pipe to pour in some vinegar, then pulled the tube and spooned in baking soda. Waiting between alternating doses of vinegar and baking soda, and listening to the reactions, I used about 1/2 lb of baking soda and 1/2 gal of vinegar over the course of about 1/2 an hour. Mainly I wanted to keep feeding the reaction and avoid having it back up and overflow the tail pipe. I was encouraged enough by the sense that the vinegar was seemingly going down to try some boiling water, but the drain would only accept about 2 cups before it backed up. I left it for a while and then noted that the water had gone down maybe a 1/2 inch. I then ran some hot water in the tub and switched to a plunger which was now feeling much different than it did initially. After a while the gurgles turned into action and the tub began to drain. A little more work with the plunger and hot water and the clog was freed and the drain was again operating normally. I was really pleased by this turn of events as my next course of action would have been to start taking apart the galvanized drain line...

So while none of this solves the riddle of how to snake this old P-trap, I'll leave it as encouragement for others to consider vinegar & baking soda, a plunger and some boiling water. Besides, it was fun!

--Larry