CANNOT UNTIGHTEN EITHER TOILET SEAT SCREWS - SO TIGHT WILL STRIP WITH ANY MORE PRESSURE. STRAIGHT SLOT - . ON A LOW PROFILE KOHLER . THERE IS NOT ACCESS TO THE OTHER END OF SCREWS EVERYTHING IS ENCLOSED. HOW CAN I REMOVE THOSE SCREWS?

No do not use metal bolt and nut as this can crack the toilet. Just go to Lowes or Home Depot and buy 2 plastic bolts , 2 plastic wing nuts, and 2 plastic washers. Install with seat through toilet holes and tighten by hand until tight. I then use pliers to tight just a turn tighter and the seat should be center as you tightened one side, then the other, and back again until tight.

You should be able to get it direct from Kohler unless you can't find it at a specialty plumbing shop .

Wrap a putty knife with a wash cloth, and push it between the toilet ceramic surface and the plastic hinge for the seat. Wedge it in there. Now try unscrewing the hinge screw. This provides back pressure against the hidden nut on the other side and may let you successfully remove the screw.

I repaied one of these laast week and it had the Plastic nuts in between the webbing on the seat where the lid connects I believe You remove the plastic cap with a knife and use a flat tip screw driver to remove the screws and replace the seat.

Here's what I did. Unscrew them as much as possible. Then I used a bolt cutter and hacksaw to cut away as much of the plastic seat holders as possible. I could then remove most of the seat, and get better access to the screws. I then raised the loose screws enough to cut them with a bolt cutter. Soft screws cut easily. The screw heads are now out. Now, tap down on the screw/anchor and it falls into the bowl. It will stay there. The remaining problem is that you need anchors to secure the new toilet seat. Kohler wants $50. I have a usable but loose seat. Never again-Kohler.
I strongly recommend using a boltcutter. A hacksaw will tear up the bowl.

Give Kohler a call AFTER you read the instructions thoroughly. Good Luck, seriously.

I have the same low boy where the bolts are inside the hollow body of the toilet. I called Kohler customer service and was told to use brute force to yank the toilet seat out. My husband suggested using a saw to cut the bolt but he hasn't done it yet. He wants to replace all our Kohler low boys which constantly leak becos of poor design of handle and flapper. The handle pulls the flapper slightly to the side when you flush. And the flapper lip being a tiny bit too small, if it doesn't sit just right, the toilet leaks. We've replaced one already with a Toto and love it. Too bad that Kohler isn't trying to fix the problem as I see many many online posts with the same problem and recommendation to replace the Kohler with Toto or somethng else.

Hacked off the old seat? You mean the closet flange that connects to the sewer pipe?
That's the part that has the bolts. They go up through the toilet base.

If you have just a straight sewer pipe now, you can connect a new closet flange to it.

1.Hardware stores sell a rubber sleeve. This sleeve fits over the cast iron, or copper, or plastic PVC pipe, and the new closet flange has a stem that fits down in the sleeve. There are two large hose clamps, that come with this rubber sleeve.

The rubber sleeve is an adapter. It adapts the 4 inch sewer pipe, down to the 3 inch stem on the closet flange. (Toilets are known as a 'Water Closet', hence the flange that the toilet bolts to, is a 'Closet Flange')

Whatever size of rubber sleeve you need to adapt two pipes together, they have it.
The new closet flange is made of PVC plastic.
(Poly Vinyl Chloride)
The flange itself is about 1/2 inch thick, and has provisions for bolts. (Use Toilet Bolts, and nuts)
Be sure the closet flange sits flush to the floor. The 1/2 inch thick rim of the flange, sits on top of the floor. The flange is then screwed to the floor with countersink head screws. The slots allow the bolts to just slip in.

IF, the flange Does Not sit level on the floor, and the area for the toilet base is not level, you need to make a flat, level surface!
Do Not half step this, or you'll have a toilet leak from now until the time you fix the floor!

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If your problem is like mine your toilet seat is loose and swivels when you sit on it. If you try to tighten down the screw it won't tighten. Use instructions above to remove old hardware.

To fix with new hardware

Purchase Hilti brand 3/16" x 2-1/2" Toggler Brand Toggle Bolt (Home Depot sells the kit). Kit comes with 10. You will only need 2. My last repair lasted about 8 years (with new kit = 40 years left or the purchase of a new toilet - whichever comes first). Set comes with 3/16 flat head screws. I recommend purchasing 3/16" 2" round head screws with matching flat washers. Sink Metal Toggler into hole with toggler pointing straight up (it's attached by long plastic legs). As it goes in the hole it opens up. Pull up on the plastic pull rings as tight as you can until the toggler is tight up against the inner porcelain of the bowl (similar to tightening cable ties). Line the seat up with the holes and it's new plastic adapter (that won't slip into the hole courtesy of Hilti). Slide washer underneath round head screw but on top of toilet seat assembly and screw directly into the newly installed toggler which is sunk in bowl/abyss receptacle. Repair should take around 5 minutes.

There are two bolts that are under cover at the back of the seat. feel underneath for the nuts-pop the caps on top w/ a screwdriver. make sure you purchase the correct profile seat Elongated or standard..