nuts and bolts

[petak]

Hi there!

I am back after a while
But still in process of renewing my R4
Process is little bit slower but still going.

I am at finishing stage of manufacturing center and rear sidemembers.

Now i have difficulty with nuts and bolt for attaching body to chassis.

According to dyalogis this bolts and nuts are M7 thread
It is very hard (almost impossible) to find new M7 bolts and nuts.
Especially if you go for stainless steel A4 material

And nut should be welded inside sidemembers

What do you think?
Should I go with M7 nuts and bolts (it will be more to original)?
Or should I go for M8 nuts and bolts?

Another thing I am worried is that steel bolts are grade 8.8 and 10.9.

I am not quiet sure will stainless steel A4 bolt have enough strength to mach 8.8 and 10.9 grade steel bolt


Can anybody tell ma why this bolt has this kind of top/peak (rounded?)

 

[angel]

The rounded edge of the bolt was there, so that the thread does not get clogged with the body-to-chassis sealant during assembly in the production line. You can't find such bolts, however normal M7 bolts will do, provided you clean the threads with a tap (may be already clean) and you pass the bead of sealant around the threaded holes.

To fit M8 bolts you have to weld nuts from the inside (there is not enough material to open out existing M7 threads to M8), and this would be awkward or impossible on most of them. It's not necessary, either, M7 bolts are up to the job.

It's not necessary to go to stainless bolts, nor 10.9 grade. 8.8 zinc plated ones should be fine, and you can put some anti-seize compound on the threads prior to fitting them, just as a precaution.
When I did the same job on my white '75, I had all bolts, nuts, washers etc cadmium plated (that goldish finish the original bits had), and therefore was able to use all the original ones.

If you still have trouble with the bolts, I can easily find M7 stuff here (even zinc plated) and send them to you. Yesterday I even bought some M7 1m threaded rods, which I always thought that was non-existant. Good searching pays off!

 

[petak]

Thank you angel.

Thing is that I am doing center and rear sidemembers from scratch.

So welding nuts from inside is not a problem.

I am double-minded between easily find stainless steel A4 M8 bolts and nuts ( but then i must change all bolts and nuts that holds body to chassis) and hard to find stainless steel A4 M7 nuts and bolts (if i do not find stainless steel A4 M7 nuts and bolt I have to go for zinc plated ones)

M8 would like because of rust free material and M7 because it is more original which i am aiming to


I am not quite sure which is better!