Start With a Rust Penetrant
Rust penetrants contain a solvent to dissolve rust, a lubricant to lower friction, and a surface tension reducer to get deep penetration. Home brews like Coca-Cola, kerosene and mineral spirits don’t have all those ingredients. Neither do general-purpose lubricants. Those products simply don’t work as well or as fast as actual rust penetrants. You can find penetrants like Liquid Wrench Penetrating Oil, WD-40 Specialist Rust Release and PB B’laster at home centers and auto parts stores.
Give them a shot of rust penetrant Soak the stuck bolts for at least 15 minutes before attempting to loosen.
If step one fails, hit it with a hammer. Create micro cracks in the rust with blows from a ball peen hammer, or even better, an air hammer and a hammer bit. Then apply more rust penetrant and “reshock” the bolt head. Repeat until you can turn the bolt. I get the best results with an air hammer and a hammer bit (GRY No. CH117 hammer bit; about $10).
Try a socket on your air hammer. Apply torque to the adapter with a wrench while you apply air hammer blows. The dual force breaks the bolt loose. I’ve had good luck with an air hammer socket adapter (No. PH1050; $53 at snapon.com). Slip an impact socket onto the adapter and try to loosen the fastener while pulling the trigger.
If neither trick works, heat and cool the bolt. The expansion and contraction will open cracks in the rust and allow the penetrant to work. But before you heat it, wash off the rust penetrant (most penetrants are flammable). Next, remove any rubber or plastic parts that may be damaged by heat. Then heat the bolt head with a propane torch. Aim the flame at the bolt head, not the surrounding metal. Heat for about 15 seconds, but do NOT get it cherry red (overheating damages the bolt’s temper, and you’d have to replace the bolt).
Immediately shock the bolt with water spray and continue spraying until it no longer steams. Once the bolt cools, reapply rust penetrant and try removing it.
Once you’re done with this project, get your vehicle looking like new with these 36 simple interior and exterior car detailing tips that you can do yourself.