Sheered (sp) bolt extraction??

[Guest]

I thought I'd stop right about here and seek advice (see photo) ... attempting to extract these 3 x starter clutch bolt ends.
Should I just keep drilling? maybe increase drill bit size one by one ? ... hoping not to mess up threads.
Should I just get it welded, or is that drag racing application only?
open to suggestions and thanx!

[JEEPRUSTY]

Take it to a machine shop and have it removed safely and properly.

[ptexotik]

Take it to a machine shop and have it removed safely and properly.

I'm starting to think the same ... and appreciate your input.

[COPSE1979]

Front engine bolt

I'm having pretty much the same issue on my 78 750.

Even though a friend and I managed to get the engine out the front engine bolt head has sheared off leaving about 1/2 inch of thread protruding on the other end but its siezed absolutely solid.

I have even tried a little trick by drilling a small hole into the middle of the alloy mount to spray in some releasing fluid. I've let it settle in over night but its still not having any of it.

Anyone else had this issue? Be happy to hear your solution. I think its going to have to be heat next??

[rapidray]

After you replace the bolts, & red Loctite them in place, if you weld the thing together you will never have this problem again. Ray.

[GregT]

For removing sheared off bolts from alloy the best and quickest method is to TIG or MIG another bolt to the visible end of the broken one.
The heat of the weld and the extra length/leverage will let it come out easily.

[argonsagas]

Here you have steel in steel and heat is often your best friend, but whenever a bolt is stuck the simplest thing to do before any other work is to strike the broken part with a hammer (or use a punch to focus the impact)

Using a penetrating oil in conjunction with this will aid you.

You need to hit it sharply, (not necessarily hard) and perhaps more than once, depending on the size of bolt involved.

The impact will often loosen the bond enough to permit extraction.

Even steel in aluminum often responds favourably.

[ptexotik]

Thanx so much guys!! I did take it to a machine shop as I felt under pressure as want to be ready for the upcoming Paso Robles ride.
And thanx Ray!! I think I will definitely go this route over winter.
Will be contacting you if you offer this service.
cheers!

[Normk]

Some good perspective on the problem in previous posts.

I have a few minutes so will try to add something in hopes that it may be useful to someone.

When a broken threaded fastener is encountered it is crucial to consider the mechanism of breakage. Why/how did it break?

Fasteners break because of excessive tension- something has "pulled" lengthwise with too much force. This is like pulling too hard on an elastic band which will stretch to some degree and then begin to yield, accompanied by internal tearing of the structure of the material, and continuing until the material completely separates. It will be noted that the stretching becomes easier/requires less tension as the yielding/internal tearing progresses.

Here's an experiment which will provide useful insight into fastener performance:

1) Acquire a 1/4" x 2" UNC (coarse thread) Grade 2 bolt & nut and sufficient flat washers or combination of flat washers and a bigger nut to act as a spacer so that the bolt is completely filled with only enough space to fully thread the nut onto the threads.

2) Grasp the head of the bolt onto your vise or hold the head by means of a box-end wrench or socket.

3) Using another box-end (ring wrench to some) or socket, begin to slowly tighten the nut against the head while paying close attention to the turning effort (torque) required to turn. If you have a beam type or dial type torque wrench to use in monitoring, so much the better but not necessary.

4) Continue to tighten noting that the effort required becomes higher and higher until, at one point of tension, the effort required to turn levels off and gradually becomes less.

5) As you continue to turn the nut, the effort required becomes easier and easier until the bolt finally pulls apart.

What has happened?

Tightening the nut, initially took up the slack in the spacer washers and threads. Next, the tightening began to apply tension (pull) to the bolt and the surface of the threads of the nut and bolt began to flatten in response to the pressure.

Once the surface irregularities were flattened out, the turning effort against the angle of the threads began to tension (pull) against the bolt in an attempt to stretch the bolt. The bolt gradually began to stretch with the force of the nut applied to the threads being greater in the threads positioned away from the end of the bolt. Starting from the end of the bolt threads, the first nut thread pulled on the bolt thread but it also pulled on all the threads beyond that point so all were tensioned.

The next thread of the nut pulled on the subsequent threads and so on inward so that the threads further in had more tension applied. Here is a first problem in nut and bolt design: The bolt's threads do not stretch evenly when the nut is tightened because the threads further in on the nut have more tension applied so stretch further than those closer to the end of the bolt.

If some accomodation is not made in design, the bolt threads would begin to fail in a dominoe manner so the nut is made of material softer than the bolt in order that the nut's threads will yield/deform to allow the nut to accomodate the stretch.

If you had a tension device, you could try another experiment but more on that later.

OK, The bolt tightened until all slack was removed, the surfaces ironed out and then the tightening force was applied to stretching the bolt. As the bolt stretches it becomes longer. Since it has a certain amount of material, making it longer must result in it becoming thinner. As the bolt material stretches (the elastic range), it behaves much as a piece of rubber in that it stretches but releasing the tension will result in the bolt returning to its original length.

Tensioning the bolt within the range in which it is stretched but can still return to original is the normal and desired condition. This is what we attempt to achieve by use of the torque wrench, torque turn method, etc. We also achieve this with the torque to yield system.

We refer to that as working within the elastic range of the material.

Once we go beyond the tension range which allows return/elastic range, we move into the tension range which begins to permanently distort/stretch the material which is referred to as yield range.

When the bolt began to stretch within the elestic range, the effort require to turn the nut and so to stretch the bolt became greater as tension was applied.

Once we moved beyond the elastic range and the bolt began to yield/the material began to permanently deform, we entered the yield range and the effort to continue to turn became progressively less because the bolt material yielded and the cross-section (diameter) of the bolt became less.

As the bolt became thinner across the body, there was less area of material to resist the tension force and so less tension (reflected in the effort required to turn the nut) was required.

Continuing to turn made the bolt stretch more, become thinner and so required less effort to contiue the process. Try the experiment again but stop before the bolt breaks and inspect the two bolts. In both cases it will be seen that the bolt thinned out or "necked out" which explains the effect.

A bolt which has broken due to over stretching is usually a bolt of much lower grade than required for the application. A stronger bolt will break without showing noticeable necking out but inspection may indicate the excessive tension effect.

A bolt which has broken under these conditions is usually quite easy to remove because it is typically free in the threads an so can be readily turned out. An "easy out" or device of this kind is in order here because what is wanted is simply some means of rotating the free piece within the threads.

This is not the state in which the bolt was broken because it was locked within the threads and broken by excessive torque (turning effort) but rather was pulled apart lengthwise.

Attempting to use an "easy out" to rotate a torque failure fastener will almost certainly result in disaster because the smaller diameter "easy out" will be incapable of forcing the piece to rotate and will likely break off in the piece, compounding the problem. I am always amazed that people will fail to perceive that a tiny cross-section easy out will be unable to over power a seized fastener when the fastener's original and much larger body was inadequate.

If this is useful to someone, please respond and I will continue in hopes that something is useful.

Norm

[themess]

NormK,

This forum has threads on broken fasteners many times every year. You have added some information that I have not read in any of those threads, and have done so in a way that is easy to understand.

Please continue.