Toilet seat hinges are loosening

I'm sorry to hear about the issue you're experiencing with your Coroma Opal II toilet seat. If you're unable to loosen the bolts that secure the seat to the toilet bowl, here are a few suggestions you can try:
1. Apply penetrating oil: Spray some penetrating oil, such as WD-40, onto the bolts and let it sit for a few minutes. This can help loosen the rust and corrosion and make it easier to remove the bolts.
2. Use a wrench or pliers: If the bolts are not budging, you can try using an adjustable wrench or pliers to grip the bolts and apply more torque while attempting to unscrew them. Make sure to hold the nut underneath the toilet bowl to prevent it from turning.
3. Apply heat: Heat can sometimes help break the bond caused by corrosion. You can use a hairdryer or a heat gun to warm up the bolts, which might make it easier to remove them. Be cautious not to overheat any plastic parts.
4. Cut the bolts: As a last resort, you may need to cut the bolts using a hacksaw or a reciprocating saw. Take care not to damage the toilet bowl while doing this.
If you're still having trouble, it might be best to contact a professional plumber for assistance. They have the tools and expertise to handle difficult situations like this without causing damage to your toilet.

If the bolts spin and don't tighten, you'll need to use pliers to grip the nut on theunderside of the toilet while turning the top of the bolt with a screwdriver. Tightenuntil the seat stops wiggling. Fortunately, there's something you can do to keep thetoilet seat from coming loose so often
Loosen the screws with a screwdriver just enough so you can adjust the hinges to reposition the seat. Temporarily reinstall the seat and lid by pressing them back down onto the hinge pins. Close the seat and lid, and align them with the front and sides of the bowl.

some of these have bolts under seat...you turn seat to left or right by grabbing while in closed position...this will release the seat from the holding bolts...then tighten the bolts....then reset the seat on bolts then lock down by doing the opposite as you took off...

If you are trying to install a standard toilet seat on a special "smooth sides" toilet, it likely will not work. Most hidden bolt toilets come with a special seat because you cannot get to anything from below. This special seat has a set of expanding style bolts that are attached to the screw that is part of the seat. The plastic expanding bolt goes into the hole(s) on the toilet, and as you tighten the screw on the toilet seat bolts, they expand the plastic part in the hole of the ceramic toilet.

hi there

this type of seat has rubber gromits that squeeze up when you tighten the screw.if it wont tighten up the gromit may have failed and would need to be replaced.

good luck

try to tighten mounting bolts be careful not to over tighten may crack poclean also see if seat has rubber gromets between hinge mount point at bowl.

I know its a long time since this question was posted but I had the same issue and have just fixed it. Remove the toilet seat by pushing in each of the two release buttons on the hinges, then lift. Where the hinges located are two circlular receivers, both have a metal cap that can be removed using a small flat head screwdriver or similar. This reveals a large cross-head bolt head on each which you can tighten. I suggest nipping them up not overtightening just in case you damage the bowl. At least once you know where they are you can re-tighten another day! Then reassemble (remembering to put the caps back on first)... I hope this helps someone - I spent ages looking for the answer on the internet only to find it all out myself. Good luck...

seat hinges were tightened out of alignment. Loosen platic nuts and tighten snugly, rotate hinges to bein line and tighten

There should be a way to tighten the bolts without going that far Here's two things:
Look at the lid, with the seat down. The bolts are sometimes covered with a snap-in palstic cap or flap. If so, pry up with a screwdriver. Then use a screwdriver and wrench to tighten.
If the bolts appear to be cast as a part of the hinge assembly, you should be able to reach around the seat to the back side (no pun intended) of the toilet, and tighten with a wrench.
I sometimes use a 'mirror trick' to get a better idea of what's back there. Just use a small mirror and hold it to where you can see the bolt and not on the back.
Hope this gets you going (oops, another unintentional pun).
Best regards, --W/D-- please feel free to rate this solution..thanx!