When you tilt the mower up on it's wheels it's critical to have the carburetor on the high side. Once you do that, disconnect the sparkplug wire and ground it. Now turn the blade straight up and down. Place a short piece of 2X4 on the ground and in the housing, against the RH side of the blade - now put your foot on it. I wear work shoes when I do this and put the sole of the shoe there instead of the piece of wood. Anyway, now you have the blade stopped so you can apply torque to the blade bolts. Usually a 1/2" drive ratchet is long enough. You set the ratchet handle off to the left so you can put your weight to work. Hit the ratchet suddenly with your max effort and the bolt should break loose. I not only do not use Loctite, I actually use anti-seize on blade bolts. I've never had one come loose.

Thank you. I have never had to use any kind of adhesive either, but I have never had such an issue with breaking the bolts free. Instead of using the 2x4 method, I was using a box end on one bolt and the 1/2 inch socket wrench on the other, using the box end to counter the rotation of the blade (and yes, I unplug the sparkplug every time I work under a mower!). I will try your method and see how it goes. Thanks again.

Impact Wrench To loosen never to tighten.

Using two wrenches like that, you are tightening one while you fight with the other one. Just block the end of the blade - the torque is reduced that far from the blade bolt and it's the back of the blade anyway, so it's not going to cut your shoe. Now on tightening, you will be blocking the sharp side so prepare accordingly.