Know-How Notes: How to Remove a Rusted Bolt
Rusted bolts stink. It doesn’t matter if the car is just a few years old or 50, there will always be rusted or seized nuts and bolts somewhere on the car. Murphy’s Law dictates that you will find those bolts when you are in the biggest hurry to complete a project. There are many ways to remove a rusted bolt. For this article, we are focusing on one in particular- Freeze-Off from CRC.
Unlike other penetrating oils, Freeze-Off adds the unique feature of hyper-cold to shock the offending part, breaking the rust bond, allowing the bolt to come out. This is achieved through the propellant and the penetrating oils. The oils are designed to dissolve rust, gum and corrosion. Freeze-Off also displaces water to prohibit future corrosion.
We had a 2009 Dodge Challenger in the shop that needed a plug removed from the exhaust. The exhaust is stainless steel, but the plug is steel. Any time you have differentiating metals, corrosion and seized threads are a very real problem. This plug was locked tight.
With the exhaust cool, we sprayed the Freeze-Off on the plug and allowed it to sit for 5 minutes.
The plug uses an Allen-wrench, which we employed along with an Ingersoll-Rand cordless impact wrench. The plug was still locked on solid.
Because the Freeze-Off has the ability to shock the part, we stepped up our game and brought out the propane torch. By heating the outside of the threads, we can expand the metal, hopefully loosening the plug. We got the part up to 366 degrees.
Before we try to turn the plug, we applied more Freeze-Off. This does a couple of things- first, the heat will pull the penetrating oils into the threads through wicking action. Secondly, by spraying just the plug itself, the Freeze-Off will cool the part quickly, providing even more shock to the threads to break the rust. With the outside still hot and the plug cold and shrinking, the bond should break fairly easy. Be careful, as this will create a lot of smoke.
Using the Allen wrench and a cheater bar for additional leverage, the plug broke free. Now the project can be finished up. Remember to use anti-seize on high-heat threads and anytime differential metals are bolted together.
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