Dana 27 Bearing Cap Bolts

While reinstalling the bearing caps on my front axle, I managed to snap off one of the bolts. I am not exactly sure why this happened, but I am guessing that the torque specs are with dry threads and since I failed to clean the oil off of mine, the bolt was overloaded before reaching the torque spec.

My question is, are these bolts anything special? Can I replace with a Grade 8 bolt from the hardware store? The originals are Grade 5. If not, is there a source for these? I am not seeing them listed by the usual suppliers.

Thanks

 

Left hand drill bit will be your new best friend. Use the other (unbroken) cap bolt for dimensions and thread length to match as closely as possible. Either grade 5 or grade 8 will work, but match both bolts on that cap with fresh bolts.
It's been a while, but Triangle Fastener on the north side of Raleigh used to be a pretty good supply. I would avoid FastenAll.
-Donny

 

I have a pile of bare housings that I can steal a bolt or ten from if you need one.

 

Thanks guys, I think I will go with a hardware store replacement to keep this project moving.

I got lucky and the remaining bolt stub came out with just my fingers. You can definitely see the stretching! So what gives? Did the oil on the threads change the clamping load by that much? I was going for 50 ftlb and never reached it. Or was this just a dud bolt?

 

Are you sure your torque wrench was set for 50 lbs? Oil shouldn't make that much difference.
-Donny

 

Yep, something is amiss. Did you chase the threads with a tap? Personally, I would be a little adverse to using hardware store bolts for that application. Almost all are now chinese and you really don't know if they are actually grade 2, 5, or 8. I would take Daryl up on a set of used originals.

 

I may have a couple you can have too...

 

Same reason I recommended to not visit Fastenall. They have mostly Chinese questionable grade bolts, about the same as hardware store.
-Donny

 

now this just might have been a stretched bolt
I would go with OEM that's me
but as it goes with torque wrenches . was the 50 lb setting done . after you pulled it out of drawer and it had been set at 90 or higher
I have the habit of dialing them down to lowest setting before . I put it away

 

That's what they taught us to do in shop class.

 

I am fortunate to have an old school fastener place in town that sells nice American grade 8 bolts. I picked up a set of those and everything went back together smoothly. I didn't bother chasing the threads, because everything was smooth enough to thread in with my fingers. I did clean them out with plenty of brake clean though to remove as much oil as I could.

As far as the torque wrench, I do keep it backed all the way off when not in use. Admittedly it is older and has never been recalibrated. Before I put the bolts in this time I checked it and another torque wrench by feel in a bench vise. They were roughly the same as far as I could tell.