Hello all,
I just finished reading an interesting thread on pinch bolts, stress, and stretch.

When replacing a worn out, rusty fastener, how do you determine which grade or material is correct?
By correct I mean " mechanically appropriate for application"
but not necessarily " show-car concours " correct...

For example, I understand that stainless and aluminum don't generally mix, and I notice that quite an number of the original stock fasteners were plated with a gold/yellow compound...

Any guidance or advice, general or specific, would be greatly appreciated.

Thanks ! ! !

Dan

 

928 specific hardware is really pretty straight forward. Everything is metric (with the exception of the seatbelt mounting bolts), there's only three 'grades' of hex bolts and socket head cap screws used- grade 8.8, grade 10.9, and grade 12.9, , and only two finishes. Everything was originally yellow cad plated, or (where the bolt would be in contact with coolant) zinc plated.


Good synopsis of the DIN and ISO standards and what the grades mean here:

https://www.fastenal.com/content/fed...ifications.pdf

 

The majority of 928 fasteners are 8.8 tensile.

Some locations like suspension bolts are 10.9 and accaisionally 12.9 - usually the workshop manual lists the grade along with thread pitch etc. on the torque value pages, so if you can't decipher an old bolt due to rust, you can look it up.

 

The pinch bolts are 12.9 grade.