How did I strip this shock mount?

[thebeerbaron]

Where did I go wrong?

72 3/4 ton, rear upper shock mount nut (leaf spring). Took the torque spec from this post:
http://67-72chevytrucks.com/vboard/s...9&postcount=16
EDIT TO ADD:

Upper shock mount is 7/16-20. Torque specs for that bolt size are about half the spec above. See http://www.almabolt.com/pages/catalo...ningtorque.htm
EDIT TO ADD:


I completely stripped the upper shock mount stud before I got anywhere near 140ft-lbs. (see attached pic)

Is the GM spec just plain wrong? Should I just be going with the spec-by-bolt-size instead?

Thanks,
Peter

[mongocanfly]

in that first link you posted it says 65lb front and 140lb rear for leaf spring and 70 for coil spring......i would have thought they should be the same...I'm thinking 65-70 is plenty...140lb sounds like way to much for 7/16...
the 2nd link don't work...

[PGSigns]

It looks be referring to the shock mount to the frame and not the shock to the mount. They just get pulled up tight. The 58 is a much better number.
Jimmy