Removing Rusted Nuts & Bolts

By February 29, 2012Bodywork
How to Remove Rusted Nuts & Bolts

If one of your hobbies is working on older cars, you’ll eventually learn one truth: enemy, thy name is RUST. What you thought was going to be a simple project can end up remaining a work in progress …indefinitely …because a nut or bolt has rusted and become one with your car. Your project has now taken up lease in your garage and refuses to pay rent. Your significant other is a broken record, asking in a loop, “when are you going to finish that thing?!” Your frustrated, tourettes-like outbursts do not help your project …or your personal life. The only thing worse than a rusted bolt between you and success, is a snapped, rusted bolt, because you didn’t know how to treat it properly before trying to loosen it – big mistake! It takes a lot more than just muscle power to loosen this partnership without breaking them.

Tools You’ll Need

  • WD 40 lubricant
  • PB Blaster Penetrating Catalyst
  • Window putty
  • Vise grips/pliers
  • Socket wrench
  • Small wire brush
  • Dry cloth

1. Use a Small Wire Brush to Clean off the Rust

Remove all rust from the root to the tip of the threads, so the nut doesn’t seize suddenly as you’re twisting it off. Be sure the bolt is actually rusted and that it’s not locking compound that’s causing the problem. Many factory bolts have thread locker on them, and this can be softened with heat. If this is the case, see the “heat removal” section at the end of the guide.

2. Spray it with WD 40 or Other Lubricant

Once you’ve sprayed in the nooks and crannies, take a hammer and tap the end of the bolt, screw or the nut’s head. This will allow the WD 40 to penetrate the grooves of the thread more thoroughly. Let it sit and soak for a bit – this can take only 5 minutes for quick fixes or up to several hours for hard jobs.

4. Select the Proper Tools

For instance, open-end wrenches are likely to round off the flats of a stuck nut, which is also why a 6-point box end is better than a 12-point one. A smaller nut gets a better fit with a smaller metric or SAE size. For example, a 1/2″ socket (12.7mm) may be a better fit on rusted 13mm nut.

A breaker bar or long handled ratchet will give you more leverage. Always use steady, even pressure, paying close attention to the feel of each turn. If the tension suddenly becomes soft, you are either breaking the bolt or stripping the threads. Wearing padded mechanics gloves will also cut back on bumped knuckles.

Carefully use your pliers to test the bolt and see if it works itself loose. Be sure you’re turning it the correct way! It’s easy to get your spatial directions confused when working reversed or upside down. Exception: Most threads loosen to the LEFT, but some ring gear bolts and old sixties Chrysler lug nuts are backwards, and loosen to the RIGHT.

5. Submerge the Nut in Lubricant

By now you’ve guessed that this isn’t a quickie – this baby wants to cuddle all night. If possible, build a cup to contain the WD 40 over the bolt or screw head. Window putty, or modeling clay works well to build a small cup around the bolt. Be generous with your putty, especially at the base, so the cup will not leak when lubricated. Fill the cup with WD 40 and let nature take its course. After a few hours, check to see if the bolt can be moved. If it’s still stuck, use a rag to mop up WD 40 from the bowl, hit the bolt with a hammer to jolt the metal, then refill the putty cup with more WD 40. If she still won’t budge by morning you have a stage 4 “clinger” on your hands, and it’s time to try some tough love.

6. Spray the screw or nut with PB Blaster Penetrating Catalyst.

This is simply a penetrating oil designed to remove rust on screws, nuts and bolts that are stuck. When trying to remove a reluctant bolt, choose a quality socket wrench with as much leverage as space permits. Firmly place the wrench over the bolt, keeping the wrench as far down on the bolt head as you can. The goal is not to chew the bolt’s head off. If the head of the bolt gets destroyed, then, you’ll have to drill it out. With persistence and proper lubrication, stubborn rust can be softened. Never re-use a rusty bolt, screw or nut when putting your project back together. Always start fresh, with a new screw or nut.

7. Pack some heat.

Heating one side of the nut with a hand-held torch can expand it enough to break the rust bond or melt locking compound. First, be sure to clean off all the WD 40 and only use open flame in safe areas. Many modern cars have extensive amounts of plastic that can melt and/or catch fire. Have a spotter watch for smoke or flames. Fireproof welder’s blankets can also be used to protect vital car parts and paint.

8. Melt a candle stick over the threads.

Heat the nut until it glows red and immediately place a candle stick over it. The wax will melt into a thin liquid and work its way into the threads acting as a lubricant. Be sure to use a snug fitting, proper sized socket.

9. Use a pneumatic or electric impact gun as a last resort.

It’s tempting to just bust out your impact gun from the start but it often breaks the bolt. Since these tools can be quite powerful, they are reserved for larger nuts. If possible, use the impact on the nut side and hold the bolt with a wrench.