Frozen Tank Bolts

I have a 1978 Norris toilet that is leaking between the tank and bowl when the flush valve opens. I attempted to remove the tank in order to replace the tank/bowl gasket but the two nuts are frozen on the bolts. I soaked them with WD40 without success. I had this same problem with another Norris in the same house a few years ago without the frozen bolt problem, just finding a gasket that would work. What do real plumbers do get these bolts out? Thanks for your help.
Gary

WD-40 is a water displacement agent and not a penetrating oil. Try using something like Liquid Wrench and see if that helps. However, in some instances all that will work is a hacksaw blade, elbow grease and patience.

bolts

The other one probably had brass bolts and this one has steel bolts. A SawZall with a long blade or a hack saw blade be itself will cut the bolts between the bowl and tank, then use brass bolts for the replacement.

Thanks for the help.

I'll give it a try.