Disk brake rotor shield, buy new or restore?

[Douglas M.]

Cover plate, rotor shield, whatever it is called.

All four of my shields are rust free, and original with nice crisp GM part # stampings, but the original zinc plating has turned a powdery white color.

Are the new shields that are available from Paragon, et al, for ~$30 each identical to the originals, or can they be spotted as replacements?

If they are diff from original, does anybody do restos on these, at some sort of economical price?

Thanks,
Doug

[Edward J.]

Re: Disk brake rotor shield, buy new or restore?

Doug, the original shields for the front were white zinc with a gold hue, the rears are like a galvinized metal. I believe most of the suppliers you buy the plates from use Zinc Chromate plating. Your better off with originals, My 72 I brought my front backing plates from Amercias Finest out of California.The rears I do not know if anyone will redo the rears as the factory did. and there are a lot more work to replace. it requires removing the rear hubs.The best time to replace them is when your having your trailing arms rebuilt.

[Patrick H.]

Re: Disk brake rotor shield, buy new or restore?

Try putting some of your favorite oil like Pre-Lube 6 or similar on them. It will minimize the white effect.

As noted by Ed, you really don't want to replace them unless you're doing the whole arm, and then I'd get the originals replated.

[Douglas M.]

Re: Disk brake rotor shield, buy new or restore?

This is a piece at a time resto.

I will be taking the front suspension apart in a week or four to get everything spotless, and restored as necessary.

The rears may wait until I am really , really old, unless something needs to be done to the trailing arms, sooner, or run out of things to do.

Any suggestions on a plater that can do the fronts correctly?

Thanks,
Doug

[Terry M.]

Re: Disk brake rotor shield, buy new or restore?

Looks like Doug has a 1972. My experience is that all four backing plates are silver colored on 1970-1972, but WTFDIK.

Edit add: Patrick looks like you might have a chance to look at this issue Saturday.

[Paul O.]

Re: Disk brake rotor shield, buy new or restore?

I agree with Terry all 4 dust shield had a silver finish have never seen a gold wash on the front shields. Here are some photo's from a BowTie 72 and as Ed stated some what of a galvanized look to the rear shields.

If my memory is correct the front were produced by Delco Moraine and the rears were a GM manufactured part and that is why a finish variation.


Paul 18046

[Terry M.]

Re: Disk brake rotor shield, buy new or restore?

A while back Joe Lucia posted that the fronts were plated after forming, thus the edges are plated, but the rears are stamped from plated sheet, so the edges are raw. A certain about 4-mile 1972 confirmed (at least to me) Joe's assertions. Additionally on that car one can see the ARMCO material ID stamping that was on the sheet before one of the rear backing plates (dust shield) was formed. Having the opportunity to "study" Bowtie Corvettes is one of the joys of the National Convention.

[Edward J.]

Re: Disk brake rotor shield, buy new or restore?

I agree with Terry all 4 dust shield had a silver finish have never seen a gold wash on the front shields. Here are some photo's from a BowTie 72 and as Ed stated some what of a galvanized look to the rear shields.

If my memory is correct the front were produced by Delco Moraine and the rears were a GM manufactured part and that is why a finish variation.


Paul 18046

Paul, I Thought the JM says something about the fronts having the chromate dip, is that a gold color? over the white zinc.

[Paul O.]

Re: Disk brake rotor shield, buy new or restore?

Ed the color of Chromate dip on zinc can be clear to blue to yellow to gold to olive drab and black. I personally have dissembled 30+ 70 to 72 Corvettes and have yet to see a yellow or gold shade on them even in the none exposed areas.

Now the later model C3's the gold finish is there and the Bowtie cars I have viewed still had the gold finish. We are only talking a few years from the 70-72 cars. When you see the gold finish on the later model cars they are not turning to silver some are still a very rich looking gold.

Paul 18046

[Terry M.]

Re: Disk brake rotor shield, buy new or restore?

Paul, I Thought the JM says something about the fronts having the chromate dip, is that a gold color? over the white zinc.

Yes Ed, it does -- after a fashion:

Brake Backing Plates
Original brake backing plates were dull cadmium or zinc plated; however, the latest Chevrolet prints have specifications calling for a chromate dip over zinc plate."

Perhaps we should have made clear that "the latest Chevrolet prints" = 1993 when this text was written. For many years the SERVICE backing plates were available in a chromate dip = gold color.