Top fixing loo seat issue

NornIronRose

Hi all. 
I bought a new loo seat and decided on a top fixing one purely because it's really difficult to get at the underneath on the wall side (small bathroom). 
There are plastic fittings which go in the holes but for some reason they aren't staying solid when I have screwed the bolt in from the top completely. As soon as I move the seat the plastic bit just pops back up. 
It is as if the plastic bit should expand more under the hole when I screw the bolt in but it isn't doing that. 

If anyone has a clue where I'm going wrong I'd really appreciate it. I've watched lots of youtube videos but none seem to address this issue. I've been fighting with it since yesterday and feel as if I'm just wasting my time. It should be easy! 

grumbler

A photo of the plug will be more informative than 100 words. Is it about the same diameter as the hole?

NornIronRose

Top picture shows that I can pull it straight up even when I have tightened it. Bottom picture is what it looks like from underneath. 

NornIronRose

This is it without being screwed in. 

Murmansk

Is there a metal nut inside the plastic at the bottom of the fixing? If there isn't then take a look at the other fixing and see if there's one there. I'm wondering if you've lost the nut/s as on the ones I've used it needs a metal nut in order to get enough grip to pull the plastic up to solidify the fixing when you tighten the bolt.

NornIronRose

No nut. I have gone back to the packaging a few times to check as that would make sense. Will have a look and see if I can find a couple to fit. 
Only problem is that I won't be able to use a spanner to tighten under that wall side. Maybe a wing nut would be a good option. Should be able to tighten enough by hand maybe. 

Thanks for that guidance. Sounds like a good plan. 

grumbler

I'm sure the bottom part of the plug is a plastic conical nut and no extra metal nut is needed.

Just  tighten the screw harder, so that the plastic conical nut pushed apart the halves of the top part more, and I don't see how in this case it would be able to pop up when pulled.

amanda1024

I’ve just fitted one of these - I think you just need to tighten the bolt quite a bit further so that the plastic distorts and holds it in place.

NornIronRose

I've had to give up. Genuinely can't get it screwed down any tighter but it just isn't opening the plastic bit enough underneath to hold in place. Don't want to knacker the head of the screw. 

I have a few jobs for my handyman friend to do so will just have to leave it for him. 

MikeJXE

Looking at photo 2 the plastic bolt looks too long or the porcelain is too thin or the hole too big

I have fitted a few of these and never had that trouble 

NornIronRose

The plastic plug pushes into the hole perfectly.  Have to really push but then it fits exactly. 
Just as soon as the seat is lowered the plug lifts back out of the hole by about half an inch. Didn't find any nuts to fit the bolts. And really I shouldn't have to be faffing around with bolts underneath as I bought this so that I didn't have to.