bolt grade

[E30_fiend]

I need to replace a few bolts from the diff where it mounts to the subframe. The bolts I pulled off are grade 8 M12x1.5 bolts. I went to my local bolt supplier because my metric bin didnt have the 1.5 thread pitch. The only bolts they had in the size I needed ad thread pitch I needed were grade 5 bolts.

No my question is this. Was BMW being anal by putting grade 8 bolts in there or would a grade 5 bolt wor just fine? This is one of those things that you really dont want to take a chance on you know?


Can anyone help me out?








Taylor

[whiltebeitel]

You could use the grade 5 if you are nice to the car, but i'd only suggst having them in long enough to find the grade 8's.

https://www.mcmaster.com

[Stevie30]

Go with the grade 8. Don't shortcut safety.

[E30_fiend]

I understand the safety thing but what i meant was BMW just being overly safe? The grade 5 bolts are still really strong but just not the strenght of grade 8

[rThor432]

Hard to say about the grade. I personally would go with the grade 8 bolts just because of all of the stress those bolts see, as you know. I've seen those bolts back out on track cars that are driven on the street. The vibration gets to them. If they see enough stress to break them loose when properly torqued, I might worry about what would happen with a grade 5 bolt.

Hope that makes sense and is relevent enough. Just my thoughts on the subject.

[E30_fiend]

Hope that makes sense and is relevent enough. Just my thoughts on the subject.

thank you

[StereoInstaller1]

I would get out the phone book and find some Grade 8.

GL!
Luke

[JGood]

Grade 8. Unless you want to replace your axles, wheel bearings, diff bearings, driveshaft, etc.. when your diff falls down on the highway.