Stripping Front Sway Bar Bracket Bolt Holes

[cham]

Few years ago I was replacing my sway bar bushings and I stripped one of the upper bracket bolt holes.  Years later I finally decided to get around to fixing it.  Tapped some new M12-1.25 threads (original are M10-1.25).  When assembling I decided to unbolt the other side bracket to add some anti seize to the bolts just so this doesn’t happen in the future.  When torquing to spec (46-65 ft-lbs) I started stripping another upper bolt hole.  What gives!!

 

I believe the original stripped when I was removing the bolt because of how corroded everything was (the bolt took the hole threads with it when un-bolting) but why are other fasteners stripping when I’m just torquing to spec (set to 55 ft-lbs)?  Anybody else have similar issues.  1.25 threads sound a little fine for this kind of load to me.  Could the antiseize be lubricating the bolt causing overtorquing?  

Edited August 12, 2023 by cham

[hawairish]

I think I've seen a stripped one on a buddy's R50 before, so I guess it happens.

And yes, applying a dry torque spec to a wet fastener results in more torque being applied.

[Slartibartfast]

If one hole was weak enough to strip, and they're in the same area on the same truck, I would not be surprised if the others were similarly compromised. And, yeah, lubed threads can cause overtorquing (if the spec assumes they're dry). You may be giving weakened threads more torque than they wanted when they were new.

 

 

[cham]

Thanks guys yeah your assumptions were correct I ended up having to re-tap all 4 upper bolt holes for M12-1.25 which I enjoyed immensely being on the ground underneath.  I guess I was surprised because the original stripped hole came from a corroded frozen bolt ripping out the hole threads using an air impact when disassembling where as the others were just giving way while assembling.  Almost looked like helicoils in the holes from the factory when I was drilling it out but I digress.  Still only torqued to 40 ft-lbs because of my fear of it happening again; also got rid of any evidence of antisieze as well but I'm confident now this was not the source of my front end clunk.  Cheers guys!

Edited August 14, 2023 by cham