Leaf Spring Swap. Retorque Everything!

[KaiserM715]

I am really not following the logic. The safety wire is to prevent back-off, if installed correctly. It is used exactly for this application by racers, the military and in aerospace.

Here is some more info:


http://en.wikipedia.org/wiki/Safety_wire

 

[Jimbo]

Have you ever tried to break safety wire? Safety wire is designed to do exactly what Kaiser is saying. I've seen components break in half before the safety wire snapped.

 

[KaiserM715]

As a followup, this is a shear application, bolt preload is not nearly as important as in a tensile application. Even if the nut was to loosen, as long as the bolt and nut remain engaged (and the threads are kept out of the bearing area of the spring mount), you would be OK to drive to Baja and back as the leaf spring would remain in place.

 

[treypal]

As a followup, this is a shear application, bolt preload is not nearly as important as in a tensile application. Even if the nut was to loosen, as long as the bolt and nut remain engaged (and the threads are kept out of the bearing area of the spring mount), you would be OK to drive to Baja and back as the leaf spring would remain in place.

Which I pretty much did... Luckily it didn't beat up the threads.

 

[beachz]

High frequency vibration is the root cause of fasteners/threads losing torque. Threads of any class subjected to the right vibration can potentially become compromised. Suspension parts are subjected to exactly this type of vibration and even more so in the environment where we run our trucks. Add to that the constant back and forth rotation that some suspension parts are subjected too.

That is one the reason anaerobic thread lockers work well. They reduce the potential for micro movement when subjected to these frequencies and rotating forces. In addition, a physical thread locking device like nyloc, locknuts, and lockwire can do the same thing and keep the nut from backing all the way out when the torque has been lost.

I have been in an environment where we had to measure and record break torque on large fasteners that were subjected to extreme temperature changes and constant vibration. Fasteners that were both Loctite (or similar) and lockwired with Inconel lockwire consistently maintained their torque values. Keep in mind that different types of fastener material will also influence the characteristics of releasing torque but we don't need to get into a bunch of metallurgy.

I guess my point is that it is NEVER a bad idea to lockwire your fasteners if there is a chance that they could be compromised... and a little Loctite never hurts.

 

[The Car Stereo Company]

cmon guys, its an easy solution. just take a pair of vise grips and grab the threads of the bolt that are sticking out from the nut........... vioala. bolt wont come out....

 

[beachz]

cmon guys, its an easy solution. just take a pair of vise grips and grab the threads of the bolt that are sticking out from the nut........... vioala. bolt wont come out....

Don't think for a second I haven't ridden home like that... on more than one occasion. Hell, I rode home over forty miles with vice grips clamped to the end of a throttle cable after I destroyed my entire throttle assembly... on a two stroke. My buddy asked me how I was still doing wheelies. Leverage brother. Never leave home without out your vise grips.

 

[treypal]

Don't think for a second I haven't ridden home like that... on more than one occasion. Hell, I rode home over forty miles with vice grips clamped to the end of a throttle cable after I destroyed my entire throttle assembly... on a two stroke. My buddy asked me how I was still doing wheelies. Leverage brother. Never leave home without out your vise grips.

They make great brake line caps too.

 

[dkfc13]

Group buy on Torque + Angle guns?

 

[Yukon Joe]

cmon guys, its an easy solution. just take a pair of vise grips and grab the threads of the bolt that are sticking out from the nut........... vioala. bolt wont come out....

That's called staking the threads.


Thanks for the clarification on the lock wire. I've seen out used in gas turbines and expanders. The way it was explained to me was that the purpose of the lock wire was to keep the nuts and bolts from going through the engine when they lost their hold strength from the original torque. It wasn't explained as a way to hold that torque in place.

However in this case of the leaf spring bolt and nut, the head of the bolt could be lock wired to prevent any rotation which would loosen the lock wire on the nut side.


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