67 rear spring to trailing arm bolt and nut

[Randy R.]

What is the finish on the nut that threads on the bolt securing the rear spring to the trailing arm? The bolt according to the judging guide is black phosphate. It does not mention the finish on the nut.

Thank you.

[Joe L.]

Re: 67 rear spring to trailing arm bolt and nut

Randy-----

The original bolt, GM #3831585, did have a black phosphate finish. The original nut, GM #9418843, had a "plain" finish (i.e. natural steel with no corrosion-protective finish, at all). Consequently, it rusted rapidly.

In case you're interested, the cotter pin used, GM #103386, had a "plain" finish, too. It rusted in no time flat, also.

[Randy R.]

Re: 67 rear spring to trailing arm bolt and nut

Thank you for the information.
Randy

[Mike M.]

Re: 67 rear spring to trailing arm bolt and nut

Cotter Pin with a 6 digit part number, what year would that have entered service?
Thanks,
H. a. N. D.

[Joe L.]

Re: 67 rear spring to trailing arm bolt and nut

Michael-----

Likely, in the 1930's or before. I can say, for sure, that it existed in 1953 and I'm quite confident that it was in existence way before then.

These cotter pins are long-lived part numbers, though. Virtually all the english size cotter pins in use today or remaining available in SERVICE are from this 6 number series.

These cotter pin part numbers trace their lineage back to GM standard specs for fastners adopted a LONG time ago. Many of the other fastners that were part of the original specs have been discontinued or superceded by now. However, cotter pins, being the simple things they are, haven't really needed revision and, thus, have survived under their original specs and part numbers.

[Mike M.]

Thanks, Joe. Some things stand the test of time. *NM*