1968 Bumper Hardware

[William H.]

Is there an easy rule that all bumper washers are zinc? If a bolt is phosphate, is the lock washer also? Thanks for your expertise.

[Gary B.]

Re: 1968 Bumper Hardware

Is there an easy rule that all bumper washers are zinc? If a bolt is phosphate, is the lock washer also? Thanks for your expertise.

William,

Based on my research, the bumper-related lock washer that was used in 1966, GM # 103328 (I'm guessing this was still used in '68, but you can confirm this by looking at the '68 AIM, if you have one) was plain or black phosphate, not zinc/cad. [As an aside, I believe all 103xxx lock washers were plain or black phosphate. Washers that were zinc/cad would have had a part number not starting with 103.) For '66, lock washer 103328 was used at all bumper bolt locations, which means it was used with zinc (or cad) bolts (which were used at all but 4 bumper brace/attachment locations), and that same lock washer was used at the front center brace location, which were a total of four black phosphate bolts & nuts in '66. So, there could not have been a rule that the lock washer had the same finish/plating as the bolt/nut it was used with.

Gary

[William H.]

Re: 1968 Bumper Hardware

Thanks, Gary. Very helpful. Do you do replating in your business or just resell? Bill

[Gary B.]

Re: 1968 Bumper Hardware

Bill,

I don't do any replating.

Gary

[Gary B.]

Re: 1968 Bumper Hardware

Bill,

I have a follow-up question for you. Where the majority of bumper bolts used in '68 plated zinc or cad? As opposed to natural or black phosphate?

Gary

[William H.]

Re: 1968 Bumper Hardware

I'm by no means an expert but most of the bumper bolts I removed from my 68 were black phosphate. There were only 2 in the front that were zinc.

[Gary B.]

Re: 1968 Bumper Hardware

I'm by no means an expert but most of the bumper bolts I removed from my 68 were black phosphate. There were only 2 in the front that were zinc.

Bill,

In terms of plating, that's the reverse situation from the mid-year bumper bolts.

Gary

[William H.]

Re: 1968 Bumper Hardware

Is it possible to have some fasteners not marked with a letter identifier of the manufacturer? I found some on the car without markings except for grade and thought they were original. I also found one's with NAT and wasn't sure if that was an original supplier. Thanks for your expertise.

[Gary B.]

Re: 1968 Bumper Hardware

Bill,

Yes, NAT is an original headmark, at least for '66 is was.

Regarding bolts with no headmark whatsoever, if you're talking about standard hex head bolts then off the top of my head I'm not aware of any such bolts for '66, although I'm not a headmark expert by any means. My guess is GM required headmarks on standard hex head bolts above a certain size at least for QA and traceability reasons in case a bolt on a structural part failed. But I'm sure others know more about this issue than I do.

Gary

[John H.]

Re: 1968 Bumper Hardware

if you're talking about standard hex head bolts then off the top of my head I'm not aware of any such bolts for '66, although I'm not a headmark expert by any means.

Gary -

I'm not a headmark expert either, but this one is my favorite.


HeadmarkJH.JPG

[Gary B.]

Re: 1968 Bumper Hardware

John,

You have to thank your parents for that match.

Gary