How to Fix a Leaky Shower Drain – take apart the shower drain and remove the bad rubber gasket. This repair is continued from How to Fix a Leaky Shower Drain – Part 1.
Shower Drain Repair: Take Apart the Drain
Because I could see water was leaking from the shower drain and dripping off the PVC U-bend onto the drywall ceiling, the next thing to do is take apart the shower drain to see if I can find why the drain is leaking.
Working in the shower stall, remove the two screws that hold the strainer in place. Be careful not to drop the screws into the drain – not that this every happened to me! A dropped screw can be retrieved from the drain U-bend with a magnetic pickup tool.
The shower drain strainer and two screws:
The house is a bit over 9 years old and I couldn’t unscrew the strainer body by using just my thumbs. A set of channel locks is used to get better leverage and break the strainer body free. The strainer body unscrews counter-clockwise, remember: lefty-loosey, righty-tighty. It didn’t take much force with the channel locks. A shower drain tool may be needed, especially if your drain has square notches for the drain tool.
The Pasco 7099 Shower Drain Wrench is a better choice than channel locks for unscrewing the drain.
I saw several problems when I removed the shower strainer body:
- The plumbers putty was brittle and chalky from age.
- Water was seeping between the strainer body and drain body.
- Lots of crud had built up around the rubber gasket that seals the drain to the shower pan.
- Water was leaking around rubber gasket.
The plumbers putty is brittle and flaked off in chunks.
I pushed the shower drain body to the side with finger pressure to better see the condition of the rubber gasket. (Note to self: Don’t chew on fingernails.)
I pulled out the old rubber gasket. It was wet and the cardboard friction gasket had mostly rotted away.
I moved the drain body from side-to-side to clean the crud from the bottom of the shower pan and the rim of the drain body. This area has to be clean if the new rubber gasket to be water tight.
Leaky Shower Drain: Cracked Strainer Body
I cleaned the strainer body thinking all I needed was a new rubber gasket and plumber’s putty to repair the shower drain. It wasn’t possible because shower strainer body is cracked in two places along the rim. Note the V-shaped cracks at the 12 o’clock position:
Cracked rim of the strainer body:
Cause of the Shower Drain Leak
I believe the shower drain leaked when the plumber’s putty became brittle from aging, shrank and relaxed the pressure that sealed the rubber gasket. The plumber’s putty cracked away and the unsupported rim of the drain body split over time from stepping on the drain.
Note that the purpose of the plumber’s putty isn’t to prevent water from running down the side of the drain body – in fact, that’s why there are the vertical slots in the threads, to channel any water down the drain. Rather the purpose of the putty is to act as a “thread locker” to prevent the threaded drain body from working loose, thereby relieving the pressure on the rubber gasket. The rubber gasket is what makes the watertight seal between the drain and shower pan. Shower drain manufacturer’s often call for a bead of silicone caulk on the bottom of the strainer body rim to seal it to the top of the shower pan to act as a thread locker, no plumber’s putty required.
This repair is continued in How to Fix a Leaky Shower Drain – Part 3.