Here are a few rear control arm bolts I did not throw out. The one with two washers might be a replacement I put on 15 or so years ago (I recall at least coating it with anti-seize at the time), but the other with the bigger washer type head appears to be original. Anyone else see these types before? I don't recall if it came from the upper or lower arms.

 

Here's an original one.

- Eric

 

If you look at the assembly manual they're all the type in the pic on top except for the lower rear control arm front bolt which is the hex flange type pictured below it.
My Vista Cruiser has all original fasteners and that's the way it is.
They don't show washers on any of them in the book.

 

My rear lower arm bolts looked like yours, sans the washers.
Here is what I found early this year:
https://classicoldsmobile.com/forums...tml#post167878
The ones with the rounded washer-like head were on the frame side.

 

That's a hex head flange bolt.
Just the two on the front of the lower control arms that type on your car too Rob?

AMK has the flange and regular type bolts if anybody needs any.

http://www.amkproducts.com/default.htm

 

The front side, or the frame side, yes...

 

Whereabouts is the hex flange one at AMK? I only see the 9421430 bolts like the top one above.

 

AMK doesn't show any of the hex flange bolts in that size (2010 Catalog). Find good used or put a good thick flat washer under a non-flange bolt.