Replacing a flush and seat on close-coupled WC

On most modern close-coupled WCs, the flush mechanism is mechanically connected and accessed from the top of the cistern, even where there is no traditional removable lid. The flush button assembly is usually unscrewed or released first, which then allows access to the internal flush valve without removing the cistern from the pan. The cistern itself is normally bolted to the pan and should only be lifted off if seals or fixings between the cistern and pan need attention. Block-style toilets typically use top-fix seat fittings, where the fixings are released from above via concealed caps, rather than accessed from underneath.

Regarding the toilet seat, most times when there is no access to the underside of the pan, like the old traditional pans, the seat has a release mechanism in the middle of the seat close to the pan. You have to lift up the seat from the pan to access the release mechanism. sometimes it is a 'silver' button that you press simultaneously while pulling up the seat with your other hand. Other times it is two little red levers that you pull together with your finger and thumb then with your other hand pull the whole seat up towards the ceiling. Once the seat is lifted, a screw driver is needed to release the two anchorage points that attach the seat to the pan. I am presuming the 'flush', as mentioned above, is the button you press to flush the loo. That too can be replaced by lifting the top off the cistern and releasing the nut that secures the button to either the lid or the boxing in behind the WC pan. And yes, the flush button, most times, is 'wired' to the syphon which is in the cistern that facilitates the flush or it is attached to the syphon via a tube. I hope this helps.

The lid always come off. .. the lid always comes off (to the cistern). Sounds like you need to call a plumber

its sounds like you need removed the pan completely for a syphon replacement also a new clamping kit probably, if you're going to do it you nay as well change all the internal parts in cistern, Some seats are designed to removed from the top / id need to see it really

On most modern close-coupled WCs, the flush mechanism is accessed from the top of the cistern. The flush button assembly usually unscrews from the top (anti-clockwise) and lifts out – it’s not wired. You don’t normally need to remove the cistern from the pan to change the flush. For the toilet seat, most modern block-style pans use a top-fix seat. The seat either releases with a push button or clip in the hinge, or the fixings undo from the top using a screwdriver or Allen key. No access underneath is required.