How do I fix my bathtub drain plug that's not working?

Question

I've looked online and couldn't figure out exactly what I need to do.

I just moved to a new flat and found out that the bathtub drain plug doesn't work well, so water leaves from the bathtub pretty quickly, even when it's "closed". I would like to know what to do to solve the issue.

Here are the facts I have gathered so far:

• My bathtub is from the brand "Grohe" (and I live in Germany, FWIW).

• There is a mechanism on the side that makes a small plastic part go up and down (when it goes up, it pushes the drain plug up to open it and when it goes down it just lets the drain plug "fall").

• The joint on the drain plug doesn't look that bad (at least to my unexperienced eyes).

• If I really push on the drain plug with my whole weight, the water indeed doesn't flow away.

What I'm a bit puzzled about:

• If it's a problem with the joint, can I replace the joint alone or should I replace the whole drain plug? Can I buy generic parts or it needs to be the exact same reference?

• Is it normal that the mechanism on the side to open/close the drain plug doesn't actually pull the drain plug down when closing it? In other words, is it expected that "only" gravity is enough?

Thanks in advance for your help and if you need more pictures, don't hesitate to ask

Answer 1

As a renter, I'd strongly suggest that a basic generic rubber bath plug (the kind you have to put in place and remove manually) is your best bet.

It will work.

It will cost much less than a Grohe replacement part, which is, frankly, your landlord's responsibility, not yours. But crappy landlords that don't maintain apartments are common.

You can take it to the next apartment, where it will also work, if that landlord also doesn't bother to maintain the tub.

Though actually...

Given where that plug seals, cleaning all the crud from the sidewalls of the drain hole may be most of what's needed to make it seal properly. Particularly the built-up patch of gunk between 3 & 4 O'Clock would defeat the rubber seal and allow water to trickle past.

Answer 2

Some tests/experiments you can perform for free, or at worst, cheap…

Bear in mind you can't get to the push mechanism without at least taking the side off the bath, so you're going to have to live with how much throw it currently has.

First, get some de-scaler [many bathroom cleaners already contain this] & liberally spray the underside of the plug & washer. It's not very scaled but it's worth a try.
As already noted by Ecnerwal, the plug-hole is pretty cruddy too. That needs a clean up as well.

That type of plug has an adjustable 'drop'. In your case the screw/nut on the end - which unfortunately looks like it's already at its shortest.

With the plug out of the hole, drop the white lever mechanism to 'closed' ie dropped. Put a blob of something greasy & visible - like bright lipstick - on the end of the plug, where the screw is. Drop it in the hole. See if it marks the white lever.

If it does, then you're out of adjustment & it can't drop any further. They're wire-driven so you can always push them a bit more closed, as you mentioned.
You could try removing the adjustment screw entirely & see if that gains you enough extra drop to stop it leaking - yet still enough rise so it will empty properly. [There is the possibility of re-jigging this with a different screw… but that's going to be very fiddly to figure out which will fit but have a smaller head...

If you just happen to have some silicone sealant & vaseline [semi-solid grease of any type] - or more lipstick at a push;) run a ring of silicone round the underside of the plug, on the chrome plate, halfway between where the washer ends & the outer edge of the chromed plate. Coat the entirety of the plug hole in vaseline/lippy & spray some water on it.
With the opening mechanism dropped already, drop the plug in the hole, press gently & leave 24 hours.
Temporary new seal - that may even last a couple of years (I've done it before & it's still working well 5 years later, but my plug is slightly more conducive than yours to it adhering well;)

If none of the above works, then take the plug to a good plumber's merchant [not a big high street DIY store] & see if they've got a replacement washer.

Good pictures & explanation, btw.

Answer 3

It looks like the black rubber seal is damaged. I am not sure if you can find a replacement seal, but you can definitely buy a replacement plug. Approach a Grohe store.

Answer 4

Start off by cleaning all that crap- which looks rather like plumber's silicone- off the chamfered mating surface of the metal portion in the bathtub.

Answer 5

Check that the central slotted piece is screwed in tightly. I fixed my leaky kitchen sink drain in this way, after finding that the whole plug/drain assembly was slightly loose and could move around, allowing water around the outside. Yours looks to be a similar design.