Hardened stainless can be as strong as grade 8 or better. What drives me to search for preservatives for these trucks? Why would anyone choose totally rust proof fasteners, non-magnetic, that looks almost exactly like the now (extremely hard to find due to new EPA regulations)cadmium plating that was original to the trucks? The answer is now that they come in button head (looks VERY much like original except rather than clutch head, they are allen head) it makes enough sense to do. Stainless suppliers have really picked up their game. You can get grease zerks as well as most brake blocks and unique fasteners ALL in stainless.
You can get a free catalog from Totally Stainless and then you will have educated yourself on what's out there. McMaster-Carr also has a great selection. Bart is pretty much right on the most these trucks need is grade 5, but what invariably happens is, people go out and purchase grade 5 bolts but forget to get grade 5 nuts to go with them.
In my case, to be honest, my restorations are so intricate and OCD over-the-top that I have to catalog ever single nut, bolt, fastener and small part on the truck, then decide on which material is best for this restoration. The one I have been working on for over a year now is a stainless project. I use 3 different grades of stainless depending on the strength needed.
The U-bolts provided by Totally Stainless use grade 8 equivalent material (a little better). All you have to be sure to remember to do is put anti-seize on the threads. Something I learned the hard way.
I just got done putting a disc brake conversion on this project and the front suspension bolts are ARP bolts that I got from Totally Stainless. Very nice stuff all around. Polished, clean looking, and very strong. So you don't have to ever give that hardware connection another thought for the entire life of the truck.
It doesn't have much to do with what is 'necessary'. What is your comfort level when it comes to several things a lot of people don't consider.. for example..
1) Is the steel strong enough to meet or exceed the manufacturers spec?
2) What is the durability of the plating that is used and will it have the longevity to meet or exceed your expectations for years to come?
3) Since restoration is more about preservation than anything, how far would you go to ensure that particular hardware connection is ONE AND DONE? In other words, will the paint and substrate fail first or associated parts?
4) If you are spending on high dollar epoxy primer, then urethane high build primer, then sealer, then topcoat costing upwards of a few thousand dollars then why would you use period incorrect zinc plating on over the counter steel bolts? Hats off to the restorers that use original bolts and have them actually CAD plated, but I cant find a CAD plater anymore, and stainless is better in the long run.
If I sound opinionated, I absolutely am. Many years as a Kansas farmers son working on these trucks with bailing wire and duct tape. Nowadays, I look for more refined ways. All while having a BLAST doing it!
