What happened to this bolt?

[Back2Braaap]

I changed my oil filter tonight. Easy project until... I replaced the two bolts. The shorter bottom one went in and tightened to 9 lbf/ft - no issues.

However the top longer one seemed not to reach the torque "click" and felt like it wasn't tightening. I removed it and it looked like the attached.

It looks like the bolt stretched... happy it didnt break inside.

 

I have ordered another one, but was wondering what could have cased this. I checked the torque and it still read 9. in fast I tested the bottom bolt and that still measured 9.

I put the bolt alongside (outside) the case and the unaffected thread is where the main crankcase is, so the "stretch" happened in the cover where there was no thread so it seems like this was a poor quality bolt.

 

I'm hoping that a new bolt will be okay and that I haven't stripped anything inside..?

 

Will a new bolt be okay..?

 

 

[Chuck.]

Over torquing stretched the bolt. You are lucky it didn't part. Probably a lot of oil on the threads which reduced friction so the applied torque put more than normal tension on the bolt.  Don't use so much torque.

[418Stroker]

I just snug mine down by feel for the oil filter cover. Sometimes small bolts can be an issue.

[Jim Dettman]

Over torquing stretched the bolt. You are lucky it didn't part. Probably a lot of oil on the threads which reduced friction so the applied torque put more than normal tension on the bolt.  Don't use so much torque.

 

 

 The owners manual also is incorrect.  The spec for that bolt is 7 ft/lbs, not 9.

 

Jim.

[mossman77]

Looks like an aftermarket bolt, unless it just appears that dark because it is covered in oil.  Regardless, get a new bolt and just hand tighten--meaning don't use a torque wrench, just a regular 3/8" ratchet and snug it up.

Edited August 11, 2015 by mossman77

[Back2Braaap]

Bought a bolt at the dealer. Went in and tightened to snug, so seems all okay. Put some white-out on the bolt (as I do with my other bolts) and will checked every few hours to see if it is moving. Should be OK, whew...

Thanks for all your support and advice.