Removing Broken Bolts, Damaged Screws, and Stubborn Nuts and Bolts

If you work on motorcycles with any regularity, you'll eventually encounter broken bolts, damaged screws, and nuts and bolts so badly worn a wrench can't grip them. Removing a damaged fastener is one of those tasks that, if not done properly, can add hours to a job, never mind drastically increasing your aggravation level. Also, verbal lubrication doesn't help get the fastener out, even if it does make you feel better. One of the features common to all the tools described in this article is that they work on SAE or metric fasteners. But before you reach for a drill, hammer, wrench, torch, grinder, or other tool, put on your goggles or safety glasses. You're going into battle!

Nuts, bolts, screws, and other fasteners rarely fail because of manufacturing defects, but it does happen. I once replaced a headlight bracket. A few months later, the head sheared off on one of the bolts even though it had been tightened to the recommended torque. More recently, while doing the first maintenance on a V-Twin motorcycle, one of the screws holding the clutch cover crumbled as soon as I put the tool on it. Some of the more challenging nuts and bolts I see are victims of corrosion, both on vintage motorcycles undergoing restoration or neglected modern motorcycles. Many of the damaged fasteners I see on newer motorcycles are the result of previous repair attempts.

Penetrating oils can sometimes release corroded nuts and bolts. These products carry names like Rust Buster, Liquid Wrench, and the ubiquitour WD-40. Many of these products are available as liquids and aerosols. Liquids allow you to put a few drops where you need them. Aerosols are handy f overspay won't make a mess. Penetrating oils won't work miracles, but they can be helpful if you're patient and allow some time for them to penetrate and do their job. I usually apply them, then work on something else for a few hours but apply a bit more liquid every once in awhile. I also tap on the head of the stuck bolt/nut, in the hope that the vibration will help the liquid penetrate easier.
Heat and cold can also help loosen some stubborn parts. The theory behind using heat and cold is that since different metals expand and contract at different rates, the careful application of heat or cold can help a slight gap between stuck parts. Many years ago, I watched the instructor in an engine repair class use a torch to heat a stud that was stuck in a cylinder head. After removing the stud, he lectured us regarding precaution that should be an extension of good sense. Will too much heat damage or discolor other parts? Does a propane torch provide enough heat or do you need a small tip on an acetylene torch? Those questions remain as valid today as they were so many years ago. However, you may not need to heat stuck fasteners now that aerosols are available to chill metal parts. These aerosol products have the advantage over a torch because they won't set things on fire or color chrome parts...

Broken bolts can be frustrating, but they can be removed with patience and the proper tools. Sometimes bolts break off at or below the surface of the part they're screwed into. This is not a hopeless situation if you have a reversible drill, left-handed drill bits, and a bolt extractor with an aggressive left-hand spiral. To use this type of tool, begin by drilling a pilot hole in the exact center of the broken bolt with a left-hand drill bit that's about half the diameter of the bolt being removed. Once in awhile, the counterclockwise rotation of the drill bit will loosen the bolt and start it on its way out of the hole. If the bolt is still stuck after being drilled, insert the extractor in the freshly made pilot hole and give it a gentle tap with a soft-face hammer. Don't smack it with the biggest hammer you own because the extractor will be extremely difficult to remove if it breaks while it's in the hole. Now turn the extractor counterclockwise using a tap handle or tap wrench. If the bolt starts turning, it's a good thing. If the bolt remains stuck, try some penetrating oil and be patient. On of the disadvantages of this type of bolt extractor is that its tapper sometimes causes the end of the bolt to flare out and fraction of a millimeter and become firmly wedged in the hole. An alternative is the power drill-out, which we'll cover later.

Screw heads are often damaged by using the wrong tools. For example, using the wrong size of Phillips screwdriver can ruin the screw's head and cause excess wear on the screwdriver. Substituting an Allen wrench for a Torx driver is a sure way to damage the fastener. To cope with damaged screws I use Screw-Outs. A set of three Screw-Outs accommodates a wide range of slotted, Phillips, socket head, or Torx head screws. Using a Screw-Out is fairly intuitive, but you must be patient. Screw-Outs usually have 6.35mm hexagonal head and can be used in cordless screwdrivers or ratchets meant for that head size head. My personal preference is a ratcheting T-handle because a cordless screwdriver set in reverse may spin the Screw-Out before it gets to bite into the head of the screw being removed.

Fasteners that refuse gentle attempts at removal can sometimes be coaxed loose with an impact driver. An impact driver is a hand tool that convert a blow from a hammer into the small but abrupt rotation of a screwdriver bit or impact socket. Impact drivers can be set for right-hand or left-hand threads. Using an impact driver involves setting the tool for the correct direction of rotation, placing the bit or socket on the drive, and giving the impact driver a hit with a ball-peen hammer while the bit or socket is firmly pressed on the fastener being removed.

This is where a large measure of good sense is important. Think for a moment: what will happen if you hit the driver too hard? Can an expensive part be cracked or broken? Don't be the do-it-yourselfer who cracks an engine cover while trying to remove one stubborn screw. By the way, only impact bits and sockets should be used with an impact driver.

More on how to get your broken bolts, damaged screws, and stubborn nuts and bolts removed tomorrow...
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