Old House Plumbing Repairs:

Replacing A Tub Drain
And Overflow Tube

In This Article:

An old brass tub drain and overflow are removed and a new PVC drain/overflow is installed.

Related Articles:
Skill Level: 3 (Moderate) Time Taken: 1 Hour

By , Editor

This is the back side of a 40+ year old bath tub. The overflow tube (the brass vertical pipe) had come loose from the tub, so water would spill into the crawl space. This I could see when I first examined the house.

But when I replaced the ancient tub faucet (which had no shower) with a proper tub-and-shower faucet, I noticed that the drain was loose where it attached to the tub. But that wasn't the worst of it...


... The drain pipes had completely separated. The pipe on the right (red arrow) is a flexible plastic drain component, and it had completely detached itself from the tub drain.

The tub had been draining into the crawl space for who knows how many years!


To begin my repair, I needed plenty of access to the area. Since this house has no basement, and a crawl space that is mostly about 2 inches deep, I decided to cut away this section of bottom plate, which was rotten anyway.


With the bottom plate out of the way, I was able to more closely inspect the pipes. I could not find a trap in the tub drain. The red arrow indicates the top end of  the flexible drain.

At this point I decided to buy a new tub drain and an S-trap.

This is the view from inside the tub. How would you like to take a nice long soak in this? (And the water contains so much iron that it is looks like dirty dishwater.)


I tried to remove the drain basket with a pair of crossed screwdrivers. There is a tool for this (called a "basket wrench", I think) that also removes kitchen sink baskets, but I don't own one.

I could not get the fitting to turn. The screwdrivers just bent.

So I used my reciprocating saw with a short metal-cutting blade.

I made a cut through one side.


With a twist of a pry bar, the drain fitting came out.


The tub drain kit. This PVC kit cost about $14 at a local home center. Brass drain kits are also available, for about twice as much.

The long rod is the connecting link for the drain stopper. That whole assembly gets inserted into the overflow tube. Adjustment of the length of the linkage is important, if it's too short, the stopper won't hold water. If it's too long, the water won't drain fast enough, and the drain may tend to clog.

PVC tub drain kit with stopper.


After I removed the old drain and the old faucet, I cleaned up the porcelain with a chemical meant to remove hard water deposits.


This is the product I used, called "Zap". It was purchased at Sam's club for a reasonable price. The active ingredient is phosphoric acid, which I have seen in other professional-grade products, and is very effective at removing mineral deposits.


This is the lower section of the tub drain.


That lower section fits into the system like this:

I assembled the drain pipes but did not fully tighten the slip-joint nuts.


After I made a test fit, I had to cut a small amount from the lower (horizontal) tube.


Since I had no helper at the time, I rigged up some duct tape to hold the drain assembly in place while installed the components from the inside of the tub.


I applied a generous bead of clear silicone caulk around the underside of the drain basket. This part is metal, while the pipes are PVC plastic.


I also applied a small amount of silicone to the black rubber gasket (that goes beneath the tub) because I knew the tub surface was rusty and rough, and I figured it would never hold water without some extra help.

There is a  risk with this approach, however. I have had gaskets get squeezed out of place because the silicone acts like a lubricant. Care must be taken to not over-tighten the basket.

I threaded the basket into the drain fitting and used a pair of pliers to tighten it.


I connected the stopper and linkage to the overflow cover plate.

I tried to estimate the correct length of the linkage, so I would not have to remove it again later for adjustments. (But I was wrong.)

Tub stopper and linkage.


On the back side of the overflow cover plate, the link attaches to the lever with a simple cotter pin.


The link comes in two sections, one of which threads inside the other to allow for adjustment of the length.


The stopper cylinder attaches to the linkage with a cotter pin.


I applied a bead of silicone caulk to the rubber gasket that seals the overflow tube to the tub.

Down The Hatch:

Placing tub stopper into overflow tube. I inserted the stopper linkage assembly into the overflow tube. It is necessary to slightly flex the linkage to make this fit. (Plastic is easier than metal.)


I installed the screws that secure the cover plate to the overflow tube.


Tub overflow tube, rear view. The back view of the above photo.

The black rubber gasket is squeezing out on the left side. This problem is amplified by the slippery properties of the silicone. If I tightened the screws further, I'm sure I could make this gasket leak.


The lower end of the drain assembly. The stopper lies right at the "T" junction, and blocks the water in the horizontal tube from reaching the vertical tube. Tub drain after installation, before installing trap.


I installed the drain cover.


The new drain and overflow are complete.

I later bought cover plates for the old faucet holes.

These cover plates were installed with the assistance of... more clear silicone caulk. See that brief article.

Tools Used:

  • Basic Hand Tools
  • Small Saw
  • Caulk Gun
  • Reciprocating Saw

Materials Used:

  • PVC Tub Drain Kit
  • Clear Silicone


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Copyright © 2001, 2005 HammerZone.com

Written February 10, 2001
Revised January 12, 2005