I'm trying to remove a tire from a lawn tractor and the bolt is stuck. I've tried all kinds of penetrating oils and an impact driver with no luck. A lot of websites recommend heating the bolt. What kind of heat source should I use?
Addition: Thanks for the tips. The problem with a breaker bar in this case is that, due to the shape of the tire rim, I need to use an extension to get a socket wrench on the bolt and the bolt head is thin so everything falls off easily.
First. I would ensure that you are using a 4-way Tire Iron. It makes you apply equal pressure to the bolt and you will be amazed at the different. In fact, if you have not tried this. Then i would not worry about the heat source for now.
In terms of the blow torch. you need anything that can throw enough heat to make the bolt almost red hot (note I say almost)
A butane torch will be totally fine. Just watch out, the hot nut will be a little easier to snap when hot.
A standard propane torch like you would use for soldering plumbing or even one of those torches you use for make creme brule will work. As others have said, be very careful of the flame and touching things that are flammable. Also, know that the nut and the stud will stay hot for a surprisingly long time. That is, in your excitement about finally getting the nut loose, don't grab a hold of it to unscrew it the last few threads and don't let it fall on anything plastic. Handle with care.
It is relatively easy to exceed the torque of a cordless impact wrench, even with a small breaker bar. E.g. with a 15" bar you need to apply 96 lbs to get 120 lb-ft.
The other thing I've tried in the past when I had a stuck bolt was taking it to my local mechanic. The pneumatic impact wrenches they have surpass anything tool you are likely to have. (Getting a riding mower to a mechanic may be a challenge.)
An old trick is to hit the bolt head with a hammer to try to dislodge it. Not so much that you distort the bolt head and can't get your wrench on, but just some to help it break loose. Also, will it help to take the tire off the rim? At least that would get it away from the blow torch. Can you apply penetrating oil to the BACKSIDE of the hub as well as the front?