Jump to content

New bolts with new leaf springs?


Recommended Posts

leaf spring bolts are fine to reuse. 

u-bolts should be replaced. generally u-bolts are single use. they "stretch" when torqued. 
however, when my rear axle had to be replaced (twice) the dealer reused the factory u-bolts,  said they were fine 🤷🏻‍♂️

Link to comment
Share on other sites

14 hours ago, Hoginedgewood said:

I'm ready to order beefier leaf springs. 2700 to 3400. I think I've seen where the front bolts are not reusable. 
are 1 year old bolts shot?  What about the U bolts?

 

 

Service manual shows only the front mounting bolt as a one time use stretch bolt so replace them.  

 

Order two new ones.  Everything else is reusable so u-bolts, nuts and the rear shackle bolts are all listed as reusable.  11602394 is the bolt you need.  

  • Like 1
Link to comment
Share on other sites

12 hours ago, newdude said:

 a one-time use stretch bolt so replace them. 

 

 

From a metallurgical standpoint I find this fascinating. A fastener stretched into the plastic zone is toast. Into the elastic limit it is reusable. Hense elastic. Once past elastic and now plastic, is has been compromised. Unstable and unreliable. :wtf:

 

Sounds like a place ARP makes a living. 

 

The Official ARP Web Site | Technical Information (arp-bolts.com)

  • Like 1
Link to comment
Share on other sites

Torque to yield bolt installation designs are used in critical tension-loaded bolts where consistency of the clamping force or uniformity of the clamping force for a set of bolts is critical. Engine head bolts, transport aircraft wing root joints, and aircraft engine mounts are some of the places I’ve seen it used.  Typically you torque to a particular high level and then rotate the fastener a specified additional amount. With these designs you are just into the beginning of the yield range with no significant necking down of the bolt section.  If you went too far it would be unreliable, but the installation using torque plus angle ensures you don’t cause excessive yielding. 
 

With all that written, though, I strongly suspect the requirement to replace this bolt if removed is not because it’s been torqued to yield.  First of all, it’s a shear loaded bolt not a tension loaded bolt, so why would the designer consider torque to yield at all. Second, the torque spec I found for the nut is 148 ft lbs. with no additional angle to be turned. Finally, I think that size bolt would require more than 148 ft lbs to yield. 
 

Instead, I suspect the bolt has to be replaced because it uses some kind of single use torque retention feature like deformed threads to keep it from loosening and coming out causing a hazardous loss of axle control. 

Edited by Another JR
  • Thanks 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.



×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.