Bolt size question

[ksquared]

It looks like I'll need 5 7/16x14 by 1" bolts to mate the Dana 20 to my top loader trans. Should I use flat washers and lock washers? Grade 5 or 8? What torque?

 

[Steve83]

Better to use flange-head (integral washer) bolts (or nuts on studs) either Gr.5 (preferred) or 8 at the same torque as the original fasteners.

 

[Broncobowsher]

That would be my choice as well. Grade 5 flange head. There are plenty of online torque spec sites for common threads. And a whole rabbit hole of thread coating variants. Dry threads, oiled threads, various coatings. How they change the clamp load vs torque. Just screw it in dry, torque to whatever online spec you find for that thread size. The window of what works is really large.

 

[ntsqd]

With the correct torque the lock-washers are not necessary or desired.

 

[73azbronco]

no lock washer, but having worked on HDs, a basic vibrator, , I always put a dab of blue locktight on.

 

[Apogee]

I'm not a fan of split lock-washers. That having been said, I am a fan of threadlocker, proper torque values and quality hardware. As for flange head versus hardened washers, there are pros and cons to each, but they essentially serve the same purpose of distributing their clamping force over a large area and preventing the head of the fastener from sinking/embedding into softer materials during installation/removal and/or over time with use. Max torque will vary depending on the grade of the fastener and to what percentage of yield you torque to, but 37 ft-lb would be typical for Grade 5 and 52 ft-lb would be common for Grade 8 UNC 7/16-14 fasteners.

 

[ksquared]

Thanks for all the input!