Frame and support colors on 1971 #1

[Ralph A.]

Can someone give me a link or send pictures of the color/shade correctness for the following components of the suspension. Bear with me if I use the wrong name for a section. Email to ralphna@bellsouth.net

Need information as Part - Gloss Black

Frame Rails including cross members -
Wheel wells -
Rear Spring mounting plate -
Front Spindle Cast pieces (2) -
Front spindles stamped piece (mine are polished) -

When the judging manual states natural finish on a cast piece is that a silver look or after it tuarnishes? Should I buff out the tarnish to a shine?

Thanks

[Joe L.]

Re: Frame and support colors on 1971 #1

Ralph-----

1) The frame was originally coated with an asphaltic coating. Medium gloss black paint approximates this color;

2) Wheel wells were blacked out with low gloss black paint;

3) Rear spring retainer plate was dip-painted with semi-gloss black; GM #1050104 (available in gallons only) is close;

4) Front spindles and attached steering arms were natural finish. This means bare, unpainted, unpolished, natural steel finish. It's a difficult finish to restore to exact original condition once lost;

5) If by front spindle "stamped piece" you mean the caliper brackets, these were originally zinc plated with an irridite (gold-colored) bright dip. If you mean the brake dust shields, these were also zinc-plated with an irridite bright dip for 1971.

[Ralph A.]

Thanks for the quick response *NM*

[Terry M.]

Dust shield color *TL*

The brake dust shields on 1970-1972 were zinc (dull silver) plated - no gold dip. For years the service dust shields were dipped, but not the production dust shields.
Terry

[Ralph A.]

Re: Dust shield color

Has anyone use the spray gold-zinc from Eastwood on the caliper bracket?
Also how about the spray zinc from same?
RA

[Joe L.]

Re: Dust shield color

Terry-----

The original front dust shields on my 69 were irridite finished. The rear shields were pre-punch galvanized (silver) material. I had them all replated with zinc, though, so they would all "match" and would all be "correct".

[Patrick H.]

Re: Dust shield color

I've used the spray gold for my headlight canisters. It looks fake and doesn't hold up well.

Send them to Steve Gregori at www.brakeboosters.com He will replate them for you, whether the silver or the gold.

Patrick

[Terry M.]

Re: Dust shield color *TL*

And all four on my 1970 were/are silver. I have seen a number of low mileage 1968-1972 Corvettes and not seen any gold dust shields yet. I have, however, learned to never say never, or always
Terry

[Roberto L.]

Re: Dust shield color

Hello, recently I finished front end resto in my 70. I found the dust shields painted black by the previous owner. That in some way preserved the original plating. When I removed the paint, found a silver plating (zinc) in rather good condition.

Roberto, NCRS #30019, RMC

[Ralph A.]

Re: Dust shield color & caliper mounting plate

My shields are zinc and are in pretty good shape. I have "cleaned them" and will not try to refinish them. By caliper mounting plates are a different storey. They were rust color so I have to buff out the rust. They are now ploished silver and I am debating on Eastwoods gold/zinc or painting them black. I do not have the eq to replate them (yet). I will decide when I finish the frame repainting and begin to re assemble.
Thanks for all the information here.
Ralph

[Joe L.]

Re: Dust shield color

Terry------

I do believe that the vast majority of the 68-72 dust shields were silver zinc finished. However, I am certain that at least one was built with irridite finished front shields. Unless someone sneaked into my garage one night and changed them on me, mine pretty much had to be original. No one else had ever worked on the front suspension of my car. And, if one was built with the "gold" front shields, then I expect that, at least, some others were.

The interesting thing here is that the GM blueprints for the 69-82 front dust shields, GM #3953423 and GM #3953424, specified the irridite dip. Somehow, at least for most of the 69-72 period, the shields were supplied and accepted by GM without the irridite finish. I wonder if, perhaps, this was an "unrecorded" change in instructions to the supplier in order to make the front and rear dust shields "match". Here's my "theory" on the situation:

The front dust shields first used for the 1969 model year and of the above-referenced part numbers did carry the irridite finish over zinc specification. The earlier 68-only shields, GM #3898011 and GM #3898012, and the 65-67 shields, GM #3864117 and GM #3864118, I do not believe carried the irridite specification and were, thus, supplied in just silver zinc. All of these shields were Chevrolet RELEASED parts, and that's significant here.

The rear brake "shields" used from 65-82 were GM #5465982, LH, and GM #5465983, RH) (it's interesting to note that this is a rare exception to the odd-left, even-right part number system for side-specific parts used by GM). These "shields" were "zinc" finished. I believe that some, many, most, or all of these up to about 1973 were actually pre-punch galvanize material. Mine were and I've examined other known-original shields which were also. However, the specs may have called for the use of pre-punch galvanize or, alternately, zinc plated. That would be a reasonable alternative and of the type often found on GM blueprints. However, I've never seen a copy of the blueprints for these REAR "shields". I SURE WISH that I had one, though. In any event, until at least 1973, I don't think that the specs for these "shields" called for any irridite dip. Also, they were not called "shields", the term which Chevrolet assigned to the front corrollary parts; they were called "plates". Curiously, these REAR shields were NOT Chevrolet released parts; they were released by Delco-Moraine. That's significant, too, in this whole matter.

I think that what MAY have occurred was this:

In 1969, the rear brake "shields" were a carry-over part from 65-68 and remained true to the original specifications, including NO spec for an irridite bright dip. The 1969 front shields were a new-for-1969 part which did carry the bright dip specification. The new front shields with the irridite bright dip were delivered to the Chevrolet component plant that manufactured the front steering knuckle assemblies and assembled into these assemblies.

In St. Louis, where the front steering knuckles and the rear trailing arm assemblies (with rear brake "shields") "came together" and were assembled on the chassis, someone may have noticed the "mismatch" in plating between the front and rear shields. Now, this wouldn't create any functional problem, but GM was at least somewhat concerned with chassis appearance as evidenced by chassis blackout, the use of phosphate-coated fastners (i.e. fastners that would look good long enough for the car to be sold), and component painting of certain chasiss parts. So, perhaps, someone decided that the front and rear shields ought to "match" with respect to plating finish.

Since the front shields were Chevrolet-released parts, the easiest thing to do might have been to "temporarily" delete the requirement for the irridite finish on the front shields. Perhaps, this was done by a simple phone call or letter to the supplier who would have been only too happy to eliminate this step which cost them extra money.

Later, about 1973, we know that the rear shields began to be irridite-finished. It may be that, by then, Delco-Moraine had been "prevailed upon" to change their spec for the shields. Or, the responsibility for the part may have been transferred to Chevrolet and the spec was changed. From that point on, the supplier for the front shields dropped the "temporary" suspension fo the irridite dip, the rear "shield" supplier conformed to the new requirement for the irridite finish, and all of the front and rear shields used in PRODUCTION and sold in SERVICE were now irridite finished.

If the above "theory" has any validity, then the only year that one might expect to find irridite finished front shields originally used on 68-72 models would be 1969. And, curiously, that's exactly what my 69 has.

[Terry M.]

Re: Dust shield color *TL*

Your theory sounds good. I was under the impression that the finish on parts was to meet a certain corrosion standard and that a specific finish was rarely specified. It was left to the supplier to meet the corrosion specification in whatever manner was appropriate.
Terry

[artarmstrong]

Part Numbers

Joe, I've mentioned this before and I'll mention it again----------------Chevrolet Engineering Specifications did NOT specify odd/even to left/right part number usage per se. Yes it generally went that way because when a specifications and or Drafting person was assigning the numbers to parts he/she would say/think left/right---in that order. And when they "obtained" a number for such L/R assignments they would take the NEXT available number from the blocks of numbers assigned to then, If that next assignable number ended in a "0" or a even number such as a "4" they would generally----it was not a requirement, but they would skip that number so that the LEFT number was odd and the RIGHT number was even. It was just something that was done, but it was not a requirement of the GM part number Specifications system.
You wrote......."(it's interesting to note that this is a rare exception to the odd-left, even-right part number system for side-specific parts used by GM). "............It was not a rare exception, It happened almost every day! Don't forget you/we are generally looking just at Corvette part numbers, which was a VERY small portion of the over all part numbers released by Chevrolet Engineering each MY . And further, if a L or R part was changed, that had already been assigned a L/R O/E part number sequence, and required a new part number to one of the L or R parts ----maybe they would be able to use the skipped part number, as mentioned earlier or have to assign it a completely different number, which is why you will occasionally find a opposite part that is not a L/R consecutive part number.

You also wrote........"Curiously, these REAR shields were NOT Chevrolet released parts; they were released by Delco-Moraine. That's significant, too, in this whole matter." ...........I just don't see how that could happen as EVERY SINGLE PART ON A CORVETTE WAS RELEASED MY CHEVROLET ENGINEERING. There was no provisions for a supplier, even a GM supplier, to release parts into the assembly plant system. In fact as I recall every part, including liquids, are issued a Chevrolet part number on a production vehicle. The only item, that I'm aware of that does not have a part number is the air in the tires. The Delco-Moraine part , or for that matter any other GM divisions production parts, that were POA (Part of an Assembly) were released as an assembled part number under a CHEVROLET part number. Yes, "other" divisions parts were released as individual parts BUT they were released through the Chevrolet system by Chevrolet. Even when the assembly plants were run by GMAD , the Corvette parts were released by Chevrolet.

Terry, to answer your question, most, if not all, parts had a GM or SAE Material specification number, for a number of items, such as corrosion, material, etc., on the drawing or written in the purchasing agreement with the supplier------GM didn't leave it to chance that the supplier would comply to such and such.

Please note that I'm not addressing the specific parts in question here, I'm just explaining the part number system as I knew and loved it. Yes there were some strange things that went on in the assembly plants--------But most of them were documented thru the releasing system and were eventually put to paper, some times after the change was made, but never the less they got documented.

Art

[Terry M.]

Thank you Art for your words of wisdom *NM* *TL*

[Joe L.]

Re: Part Numbers

Art-----

If I implied that Chevrolet Engineering Specifications dictated that left side part numbers be odd numbers and right side part numbers be even numbers, that was not what I intended to convey. Quite the contrary. If such were the case, then there would not have been a case like the one I described regarding the rear disc brake "shields". However, in my observation, at least with Corvette parts (which is usually all I'm talking about on this discussion board), about 98% of the time the aforementioned is the "convention". It's rare to see odd number-right and even number left. I think that's all I said. Or, at least, it's all I intended to say.

With respect to the other issue, perhaps I incorrectly used the term "released". A better term might have been that the front shields and rear "shields" were parts which "originated differently". By the way, are the front shields used over the 65-82 period (GM #3864117, 3864118 (65-67); GM #3898011, 3898012 (68); and GM #3953423, 3953424 (69-82))Chevrolet part numbers? How about the 65-82 rear "shields, GM #5465982, 5465983?