How can I break the big tub nut loose if I'm trying to replace the shaft/tube assembly.

SOURCE: tube retaining nut on egr valve

Try putting a little WD 40 or some kind of thread remover on the nut and let it soak overnight. Then put a good quality wrench over the nut and crank away. You might use a line wrench if you have one. This type of wrench will not strip the hex off the nut. You will probably have to put some muscle into it to get it to break free. So, watch the knuckles at the same time.

SOURCE: can't get front wheel bearing retaining nut to break loose

Air tools? good heavens. Just get some classic coca cola and wait. She goes loose left handed. But make sure you undo the fixing of the nut first (the way it is secured not to turn loose spontaineously). At some cars there is a split pin, Mazda had those deformable ones which you had to cut partially. (And new ones ready)

SOURCE: 2000 olds intrigue, changing the front wheel bearings

Well the nut is a lock nut. Your not really supposed to reuse it, and after years of use its probably a little rusty. I would have someone stand on the brake pedal while you use a 1/2" drive breaker bar and a piece of pipe for leverage to loosen them. Do not use a impact gun unless you have to, it may damage the CV joint. If you do have to, make sure someone is holding the pedal down well. It will come off, remember counter clockwise loosens it. As for torque it should be about 184ft.lbs or 250Nm. Good luck! I hope this helps.

SOURCE: how do you remove the fan from 1998 f150 4.2 liter

how do you remove the fan and fan clutch from 1998 f150 4.2 liter engine. i am trying to replace the water pump but i cannot get the fan to break loose . i cannot figure how to stop pump from turning while trying to loosen the bolt or nut that holds the fan clutch on the water pump shaft . is there a special tool to help me with this

SOURCE: can not get hub Assembly nut to break loose,even

You need heat.
I have not had very good luck from small propane torches, you will need a auto shop torch set...but,
try soaking it with penetrating oil. (Keep adding it to allow penetration over time)