How to Remove Loctite Boltsby G.K. Bayne
Loctite -- the brand name in this business -- produces what are known as "anaerobic threadlockers." The word "anaerobic" means that, unlike most kinds of adhesive, they don't need air or a second compound to cross-link their molecular strands, polymerize and harden. These compounds begin to cure simply by coming into contact with metal. They're produced an various strengths, indicated by color. Purple Loctite 222 is the weakest, and Blue 242 is medium strength. These are considered "removable," because they only hold to a certain pressure. Red 271, though, is the next closest thing to welding threads together -- so, it requires something comparable to remove.
Attempt to remove the bolt first with the correctly sized end wrench or socket. Purple 222 will break free with 20 foot-pounds of torque or less, while Blue 242 will hold to about 50 foot-pounds. If you've got red Loctite, don't bother trying to break it free; Red 271 is rated for about 3,000 psi of shear strength.
Break out your propane or acetylene torch. If you're using acetylene, you need little more than a smoky, yellow "starter" flame to heat the Loctite to its 550-degree-Fahrenheit melting temperature. The yellow starter flame provides more than enough heat to do the job.
Apply heat to the bolt head or stud with your torch, just touching the metal with the end of your flame. The trick here is to keep the torch moving around the bolt or stud to evenly heat it, and not to get in a hurry. It's best to avoid heating the bolt up any more than necessary, and to give the heat a little time to work its way down through the metal and to the Loctite. Some like to heat the bolt to a dull red to be sure, but that's a bit overkill.
With the bolt still hot, extinguish your flame and immediately fit the proper socket or wrench with a long breaker bar attached. Apply steady pressure, and the bolt should come free with little more than the amount of torque it was originally tightened to.
- Take your time when removing any bolt secured with threadlocker. Rushing the removal of these bolts that are treated with the thread-locking substance may create more work than desired.