[Help] Push and twist plugs not working

[Ron Manager]

When these stop locking in the plughole, is it the plug or spindle in the plughole at fault?

 

[Chicken Run]

have you tried pushing it in then pulling it out?

 

[Harry Wilson's tackle]

Try getting the black mold off and clean the O ring.

 

[Frutos]

Roll on Saturday.

 

[Springal]

Those things are a nightmare - normally it’s the bit in the plug that’s the problem.

I replaced all mine with flip ones like this

1 1/4" Flip Top Plug Basin Waste - Slotted - For Basin

1 1/4" Flip Top Plug Basin Waste - Slotted - For Basin With Overflow Hole. Internet Only Price. In stock: Delivery Next Day. Rated 4.7/5.

www.plumbworld.co.uk

 

[Mr Bridger]

Sometimes the rubber seal spreads out which makes it stick, try giving it a trim.
Congealed toothpaste is another factor on the mechanism, so while it’s off, clean it and give it a spray with WD40 or bit of plumbers grease.
Best thing to do is change it for a swivel waste.

Flomasta Captive Basin Waste 32mm - Screwfix

Order online at Screwfix.com. Robust, all-brass construction. Deters vandalism. Slotted for overflow. No rubber plugs and chains or complex pop-ups. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

 

[Paulie Gualtieri]

Assumed I’d walked into a tactical debate based on Fabs set up on Saturday

 

[Rowdey]

Those things are a nightmare - normally it’s the bit in the plug that’s the problem.

I replaced all mine with flip ones like this

1 1/4" Flip Top Plug Basin Waste - Slotted - For Basin

1 1/4" Flip Top Plug Basin Waste - Slotted - For Basin With Overflow Hole. Internet Only Price. In stock: Delivery Next Day. Rated 4.7/5.

www.plumbworld.co.uk

Not a fan of these - Always sticking and then need to smash them out.
OP - It'll be the piston. Bit of WD40 on it where it goes into the basket waste, and it winds out, but take care mind..
Amazon product ASIN B09FXMJD1M
Not sure if link working, but amazon uk, search for

Replacement Sink Basin Bath Pop Up Click Clack Slotted Plug Bolt Assembly Internal Spring Brass Plug Bolt​

 

[BN9 BHA]

The brass part that the plug screws onto contains a spring usually fails. You could try cleaning it as mentioned by @Mr Bridger.

Amazon, eBay etc sell the brass part separately but they are not a universal fit.