How To: Remove Rusty Pipe Plugs, Head Plugs and Screws

Rusted? Frozen? Just plain stuck? Learn tips to remove various types of stuck pipe plugs and head plugs

| May/June 1981

  • Pipe plugs

  • Pipe plugs

Pipe plugs become set in their ways, and sometimes difficult to remove. If a square head plug is to be removed, pound on the head of the plug using a one pound hammer. Rhythmic blows, not too hard, should be used and continued for a minute or more. A spray penetrant, like WD-40, always helps. Use a large wrench, like a 12" crescent to remove the plug. If the head is mutilated, a vise grip pliers may also be used.

If an allen head plug is encountered, select a drift punch as large as will enter the opening and pound on it as described. In removing this plug a socket type allen wrench is best, but a conventional "L" shaped wrench may be used if an 1/8" or 1/4" pipe about 6" long is placed over the long end of the wrench. This gives leverage and prevents flexing of the handle.

In removing any plug, cap screw, or nut, avoid using too light a handle. Flexibility of the handle will prevent breaking the plug or nut loose. If an acetylene torch is available, the plug, nut, or screw can be heated to facilitate removal.

If all else fails in removing the plug or screw, you can center punch the plug, drill it and remove it with an EZ out. A word about this process is in order. The first step is all important! This involves center punching the plug or stud exactly in the center. Look at the punch mark from several angles, realign the mark if necessary. Next select a small-approximately 1/8'-drill bit to start drilling. Hold it in alignment so you drill a straight hole. Drill clear through the plug or screw to be removed. 

Next select a screw extractor (so called EZ out) just smaller than the diameter of the plug or screw. I prefer square end screw extractors. Usually they will indicate on the shank the size drill to use for that extractor.' If not given, select a drill smaller than the diameter of the plug or screw, the extractor of corresponding size and large enough to provide a sturdy hold. Now drill the plug or stud with the larger size drill bit. Drive the screw extractor in tight. Use a crescent wrench large enough to give you good leverage and a rigid hold. Usually the broken piece can be removed quite readily, but there are exceptions. An example of a broken stud or screw that could not be removed by this method would be on an exhaust manifold. How much torque you can exert on the screw extractor depends on the size of the extractor. It is possible the extractor may break in the stud or screw.

Of course, this complicates matters, but the extractor can be removed by drilling a small hole just outside the corner of the broken extractor. With a punch and hammer, the extractor may be jarred loose and removed. Now it will be necessary to use a half round chisel or cape chisel to remove the threads of the screw or stud. A small chisel works best. I usually make one from an old drift punch of the right size. After the threads have been removed, the threaded opening can be tapped to the right size again.

There is another problem that may arise. The threaded opening may be too large to hold the stud or screw tight. The pipe plug usually does not present any problem because the threads are tapered. In case the threads are stripped, or too large, the original threaded opening size can be restored. You can obtain from a parts supplier, a Heli-coil (brand name) or insert to be drilled, tapped and threaded in an enlarged drilled hole. It requires a special tool to install the insert, but it is a relatively simple operation. The restored thread is as good, or better in the case of an aluminum casting, than the original. Specific instructions for installation come in the package with the insert.

Another problem in the area of rusted, corroded or tight fittings might be removal of a nut from a threaded rod, or a sleeve or pipe fitting from a length of pipe, or a threaded rod in a yoke. The common practice is to use two large wrenches of the correct type and twist. The result is too frequently a broken piece, a flattened sleeve or no effective separation. The secret of success is to loosen the threads before you try to separate them.

If the pieces are small enough to move, they may be placed on the anvil block of a vise, and using a suitable size hammer-again depending on the size of the pieces- pound the outer surface of the sleeve, nut or yoke as it lays on the anvil block. Rotate the sleeve or nut and pound on all sides of it. It will surprise you how easily they may be separated.

If the threaded rod or yoke is connected in such a manner that it cannot be removed before separation, use a heavy hammer or iron block such as an 8" piece of railroad rail as a backing on one side of the yoke or sleeve. Pound on the opposite side of the yoke, continue the pounding for a minute or more, as it takes a little time to jar the threads loose. If the threads are not loosened, try pounding again, you may have given up too soon.

Contact Bud Motry at 20201 Arthur Road, Bib Rapids, Michigan 49307 


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