Removing broken bolts

[enjenjo]

Moonlight, or torchlight?

headlight

[40 Chev]

Here are some tips on getting broken bolts, or bolts with the heads stripped, out.

First thing to remember, don't get too aggressive at the beginning, start with the least destructive methods first. Then you have to analyze the problem. decide if the bolt is stuck from rust and corrosion, or from other causes, deformed or bent threads, galled from heat or material properties, or the fact that the head is stripped. If the head is just slightly stripped, it's sometimes possible to get it out with a 6 point socket, or if the head has rusted to a smaller size, a metric socket will sometimes remove it. ViceGrip make some special pliers just for removing bolts with stripped heads. They are well worth the price.

If the fastener is accessible from both sides, and the nut isn't permanently fastened to the part, cutting the head off with a die grinder, or splitting the nut may be the best way to get it out. If the nut is caged, or welded to the part, you can weld a larger nut to the head of the bolt, and use that to remove the fastener. When doing this, let the fastener cool before trying to remove it.

If you have to heat a fastener to get it out, don't heat the part, heat the fastener. And let it cool to some extent before trying to remove it. You can also use heat and cooling together, heat it, and touch the bolt with an ice cube, repeating several times. You can also use penetrant or paraffin along with the heat. What you are trying to do is break the rust bond between the parts. Once you can get the bolt to move, stop and regroup. turn it one way, and then the other, adding penetrant, then work it back and forth some more. patience will be rewarded.

If the bolt is broken off, and it's sticking above the part, you can weld a nut to it, using plenty of the heat on the fastener. then, let it cool completely before trying to turn it. Put a wrench on it, and tap it back and forth to break it loose. Add penetrant, and work it out.

If it's below the surface of the part, many times you can still weld a nut, or a piece of strap to it with minimal damage to the part. Finish removing it like the case above.

If you have to drill a fastener, drill a pilot hole first, clear through the bolt if possible. squirt penetrant into the pilot hole, and let it set before continuing. Then continue drilling with a left hand bit. Or, you can use some of the new bolt extractors with a left hand drill bit built into the end. Very often the bolt will come right out.

Welding a nut to it can also be useful for removing a broken screw extractor. if that's not possible some of the other methods offered are excellent. The last resort is EDM machining, which can be expensive.

There are some special cases, one of which is countersunk screws, with stripped heads. My favorite method involves drilling the head off, separating the parts, and removing the stub with one of the other methods.

Another special case is exhaust manifold studs. Since the parts have been heated regularly, heat is not near as effective as it is in other cases. Also many times the threads have galled making it more difficult. In this case, I heat the casting to bright red, cool the fastener, and lots of patience. Once you can get it to move, penetrant, and more patience.

Steel fasteners in aluminum castings, or die cast zinc, are another special case. Most times the casting corrodes into a white powder, that very effectively locks the fastener into place. I have found PB blaster works good the dissolve this corrosion. It is of course better to free the bolt up before you break it, so I will drill a small hole in the fastener, to allow the penetrant to get to the end of the bolt. In many cases this will allow the fastener to be removed with your hand after breaking it loose with a wrench.

I personally won't use tapered extractors any more. I recently removed a broken bolt from a JD Backhoe. One of the bolts on the rocker arm broke and I was given the job of fixing it after several had tried. I used a RIGID extractor after drilling through a broken easy-out and welding etc. Here's a link to their site http://www.ridgid.com/Tools/10-Screw-Extractor-Set/index.htm

I had to use a 100% cobalt bit.

[phat46]

Moonlight, or torchlight?

headlight

 ...is that when moonlight reflects off your head?