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How to Remove Rusted Bolts

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    In browsing through many motorcycle & car repair forums I notice a very popular question is... "What is the best way to remove a rusted-on nut or bolt?"  I will share with you what I have found to be the best way based on my experience, especially after reading on article shared by one of our CycleFish members (RevBigJohn) several years ago.

     


     

    There are three basic ways to remove a rusty nut or bolt: Brute Force, Heat & Solvents 

     

    Brute Force:  I do not recommend this because the hardware is already compromised from the rust and there is a very good chance of breaking it off.

     

    Heat:  Again not highly recommended because the amount of heat you need to expand hardened nuts is extreme heat (i.e. oxy/acetylene torch type heat) and I don't really like the idea other parts around the hardware are going to heat up and may get damaged (not to mention the probable presence of gasoline or fumes around a motor).  However, in extreme situations this may be the only way to go.

     

    Solvents:  This is normally the best way because it reduces the chances of damaging the hardware or anything around it. The first thing to know about using solvents to remove a rusted nut or bolt is it takes time.  Remember it took years for the rust to build up and you are not going to free it by spraying penetrating oil and coming back 2 minutes later and try to break it loose.  Any type of penetrating oil needs time to react and break down the rust.  Depending on how bad the rust is and where on the bolt it is located, this could be 15 minutes to overnight... or longer.  A really rusted bolt that goes deep into the threads could take several days of re-applying the solvent so that it can break-down the layers of rust allowing each application to move deeper in the threads.   

     

    So, which is the best solvent to use?  That is where I found the article posted in Machinist Workshop Magazine several years back very useful.  They did a test with a variety of nuts and bolts that were scientifically rusted to a uniform degree in a salt-water solution.  The fasteners were then treated with four popular commercially available penetrating oils/rust removers and one home-made solution of 50/50 Automatic Transmission Fluid and Acetone.  One bolt was also removed with sheer force as a control. 

     

    Here are the results of the average amount of force needed to remove each bolt...

     

    Nothing Used: 516 ft lbs

    WD-40: 238 ft lbs

    PB Blaster: 214 ft lbs

    Liquid Wrench: 127 ft lbs

    Kano Kroil: 106 ft lbs

    ATF/Acetone: 50 ft lbs

     

    As you can see by the results the home-made brew of 50/50 Automatic Transmission Fluid and Acetone outperformed the commercially available solutions by a long shot.  This is why I have personally been using it since I read the article (about 5 years ago) with great success.

     

     

     

    Warning: All solutions above are flammable with the Automatic Transmission Fluid and Acetone being extremely flammable.  Also these could cause irritation to your eyes and skin if contacted.  Be sure to never use any them near an open flame or heat source and always wear chemical resistant gloves and eye protection

Comments

1 comment
  • EvilOneBrand likes this
  • RexTheRoadDog Been using ATF/Acetone mix for several years. Nothing better! Caveat is ya HAFTA be patient!