[image: View Post]checksix, on 18 April 2010 - 10:55 AM, said:
ALOC means "locking compound already applied". When you buy the bolts, they already have locktite on them. I think most people reuse the bolts several times. Just torque them to spec (don't overtorque, to avoid "stretching" them).
No, yes, yes and no...
I've never been able to find what Honda thinks "ALOC" means, but I think it is safe to say that they are NOT simply standard fasteners with pre-applied thread lock on them. I just wrote the following on another forum, and I think it bears repeating here:
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Honda does sell a thread locking compound, "Hondalock", which is available in no less than three different strengths. In the front of the Workshop Manual is a table listing the fasteners on the ST1300 where it is supposed to be applied. That leads me to believe that Honda was certainly able to specify using thread lock on the ALOC fasteners if that would have addressed all of the issues relating to those fasteners.
I think it is instructive that the torque values specified for ALOC fasteners are substantially higher than the torque values specified for "standard" fasteners of the same size. For example, the M6 ALOC front brake disc bolts are supposed to be torqued to 20Nm, whilst the highest standard torque value for any other M6 fastener on the ST1300 is only 12Nm. This suggests that these ALOC fasteners are designed to stretch a certain amount upon installation, and that Honda specifies their replacement because they cannot be safely stretched that amount subsequently. No doubt a qualified materials engineer could explain how this works better than I could.
Not only that, but the addition of a liquid thread locking compound to a fastener with a dry torque value means that if you torque such a fastener to the same value (i.e., 20Nm), the actual torque you will be applying to that fastener is 10%-??% higher than the dry torque value. So, you're effectively re-stretching an already stretched high-torque fastener with a higher torque than was specified for a brand new one. Hmmm...
I'm not saying don't re-use ALOC fasteners under any circumstance (I have certainly done that in the past), but it would probably be a good idea to understand exactly what you're doing when you do so.
I subsequently found a succinct related post on the GL1800Riders forum, which agrees with other information I've read on this subject:
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It appears to be high time to correct a few dangerous misconceptions.
First, ALL metal components stretch when subjected to a tension (stretching) load. The greater the load, the greater the stretch. When the loads are below a certain value the metal behaves in an elastic manner; that is, when the load is relieved the component un-stretches and returns to its original length. Above a certain load, the component is permanently deformed and does NOT return to its original length. This is called plastic behavior and the point where the behavior changes from elastic to plastic is called the yield strength or the elastic limit. The limit of plastic behavior is where the material physically breaks and is called ultimate strength.
The measured values for yield strength and ultimate strength are single-shot values. That means that the material will yeild or fail the first time that load is encountered. However, loads that are well below these values can cause a material to fail if they are applied repeatedly. This phenomena is called fatigue. For a steel part to have an infinite fatigue life, for example, the applied loads must be kept to about 50% of the single shot load. At higher values, the life of the component is greatly reduced; a component that is loaded to 90-95% of yeild can take this load only a very limited number of times. Oscillating loads that fluctuate between tension and compression cause even shorter lives.
The whole purpose for installing a fastener to a certain torque is to create a certain clamping load in the bolted connection. While the bolt is within its elastic range, the clamping load is proportional to the applied torque. A bolt torqued to 50% of yeild produces a certain clamp load; a bolt torqued to 75% of yeild will produce a clamping force 1.5 times that produced at 50%.
The bolt load is relieved and then restored every time the bolt is removed and reinstalled, therfore fatigue life becomes an important consideration whenever bolts are torqued to a significant percentage of yield strength. Bolts with thread locking features have their lives shortened even further as the torque to break the lock is in the opposite direction to the torque to seat the bolt.
The application of this discussion to Honda Goldwing brake caliper bolts should now be obvious: By virtue of a relatively high seating torque and a relatively high loosening torque, it is possible for these bolts to fail after one use. Many of these bolts will go for more than one use, but their safe life is limited and your brakes are no place to cheat on life-limited components.
Hang these on the wall:
1 - If a torque is specified, MEASURE IT.
2 - If a life-limit is specified, BELIEVE IT.
3 - If a locking method is specified, USE IT.
3 - Never substitute ANY bolt that has a specified torque and/or life limit unless you are sure of both type and grade.
4 - Never, ever, ever substitute some crap you rummaged up at Big Al's Hardware and Pizza just because it fits. Unless you like finding out just how crappy Chi-Com metalurgy can be.
Ciao,