Pro tip: A snapped injector hold-down bolt taught me to always use a backup wrench

I was doing an injector swap on a 6.7 Powerstroke in a shop in Boise last Tuesday. I was torquing the last hold-down bolt to 44 ft-lbs when it snapped clean off, leaving the threaded portion stuck in the head. I had to pull the valve cover, drill it out, and chase the threads, which added about three hours to the job. The lesson was that the torque spec is fine, but you need a second wrench on the socket to keep it perfectly square to the bolt head. Has anyone else had a bolt snap at spec, or is there a better method to prevent this?

3 comments

3 Comments

amy9741mo ago

Snapped at 44 ft-lbs seems like a fluke, not a regular problem. I've done dozens of those swaps and never needed a second wrench. Maybe it was just a bad bolt or a slightly off angle you didn't notice.

blair_webb1mo ago

Used to think the same way until I saw it happen twice in one week. Both times the torque wrench checked out fine later. Now I always use a second wrench to double check the click, just in case. It adds maybe ten seconds to the job and saves a huge headache. That low torque snap is rare, but seeing it once was enough to change my whole routine.

the_max1mo ago

Snapped at 44? That's wild, @amy974. I've seen them go at 60, but never that low. Makes me wonder if the torque wrench itself was out of spec, giving a false reading. A bad bolt is possible, but that's a huge difference from the spec.