The bolts connecting the components of your vehicle's exhaust system are prone to rust. When rust fills the small gap located between the threads of each bolt and the threads of each bolt's hex nut securing the bolt to the exhaust, the bolt and nut can fuse. That can make it difficult to loosen the nuts to work on your exhaust, or it can cause you to break the bolt altogether. Heating the bolt to get it off is a bad idea: Extremes in temperature can effectively break the bond between the two fasteners; also, when using heat you run the risk of creating a fire around the vehicle or igniting fumes from the fuel system. A safer alternative to heat is to "super-cool" one fastener.
Remove large rust scaling from each exhaust bolt by tapping the bolts with a hammer and running a wire brush back and forth across the threads of each exhaust bolt. Clean the loose rust particles from each bolt with a clean rag.
Shake a can of freezing penetrating oil according to the can's usage instructions.
Hold the nozzle of the spray can 2 to 3 inches from the threads of the exhaust bolt. Spray the penetrating oil on the bolt for five to 10 seconds. Allow the penetrating oil to sit on the fastener for one to three minutes.
Choose a socket from a socket set that matches the size of the hex nut connected to the exhaust bolt and atach the socket to a breaker bar. Turn the nut on the exhaust bolt counterclockwise with the breaker bar. Spray additional freezing penetrating oil on the threads of the exhaust bolt if the nut does not break free.
Push hard counterclockwise with the breaker bar to snap the exhaust bolt if the nut will not work free with the penetrating oil.
