Any tips for removing stubborn bolts?

I just picked up a new rearend for my car. The guy I bought it off just cut the control arms and dropped the rearend out of the car. Does anyone have any tips for removing those bolts. I just got in from being out there for an hour and a half and I did not make ANY progress in getting them off. I have a 5 hp compressor and an impact gun and that didnt do a damn thing. I tried a big breaker bar and once again..nothing. My only option left is a torch. Do you guys think that will get these threads to crack. I'm up here in Canada so these bolts under the car get basically welded together. Its getting really frusterating to not be making progress after working so long. So if anybody has any tips or tricks I would really appreciate it.


And one more question. If I have to use a torch to get my existing rear end out will it be bad to have to use it so close to the gas tank?
 
You live in the north where old bolts do exactly what you said. You could soak them in penetrating oil. I like PB Blast the most, soak it in that for a good hour, then hit it and if it doesn't move try using the torch to heat it up and remove the bolt. If all else fails you might have to cut it off.
 
If you soak them in anything and then use heat of any sort, be aware of fire hazzards (not withstanding normal fire hazzards).

Good luck.
 
If you end up breaking off the head, (which I imagine you will if you continue to pound on it without using penetrating oil,) just drill in to the bolt shaft, hammer an easy-out in to the hole, and give it a good smack with a mallet.
 
These bolts are torqued down to 100ft-lbs, you will need a giant braker bar to get them off. That or a torche. Dont worry about breaking them, you wont, they are extremely strong bolts. Try putting the braker bar on and kicking the **** out of it with your leg.

Btw, its easier to get those bolts off with the rear still in the car lol.
 
I got this tip from a member here. Use the penetrating oil, then put your breaker bar or wrench on the bolt, and put the handle on your floor jack. Then just jack it up. No strength needed.
 
If you are turning the bolt and it's not loosening, make sure it's not stripped. If that's the case, you will have to drill it out. If it's working it's way out, then it's just a stubborn bolt.
 
Have fun getting that thing out. the same thing happend to my quad shock bolt. it was siezed in there. I said **** it and took it to ford. Id rather pay a tech 35$ to take the bolt out then have to work in my garage for a week screwing with it. BTW it took him about 40 mins to do it, he cut it out with a torch. didnt look like he was having too much fun either. lol