[Vwdiesel] Torque to Yield

[Patrick Dolan]

The mere fact that a TTY bolt CAN be used into a range of strain that puts
it into plastic deformation without brittle tensile failure should be
telling us that they are not particularly high strength fasteners.  I
would be comfortable replacing them with 8.8 for shear bolts and 10.9 if
loaded in tension- coarse pitch for most, fine pitch if clamping a surface to immobilize a joint is the service condition.  Then, just torque to spec for the fastener size, grade, pitch and thread condition (i.e. wet or dry).



----- Original Message -----
From: Shalyn Shourds <sshourds at flash.net>
Date: Tuesday, March 1, 2011 1:00 am
Subject: [Vwdiesel] Torque to Yield

> I'm making some good progress on my '00 Jetta front end project, 
> but it 
> seems like every bolt I pull out of it is a TTY bolt.  I'm 
> probably 
> going to be out nearly $100 replacing just those.  Knowing that 
> cars 
> stayed together before those were implemented, is there a 
> guideline for 
> substituting in non-stretch bolts?  I recently did the front end 
> of my 
> '85 and I only had to replace a few lock nuts.  The system as it 
> is has 
> lasted 280,000 miles so I don't know if I'll ever have to go back 
> in 
> there again, but I guess I'm wondering just for engineering 
> knowledge's 
> sake.  I do have access to a reasonably large store whose only 
> product 
> is metric hardware, so there's a good chance that I could find 
> equivalents.
> 
> -Shalyn
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