Unpainted, machined areas on 65/66 brake calipers; A questionable area

[Kenneth B.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Ken,

In post #4 above, David asked where the information about the black paint first shows up. I’m curious as well. I’m aware that the painting description is widely quoted.

Gary

GARY
Not sure what or why it important to know when it was added to the JM but I build patterens for some of the foundries that cast them & watched them being painted on hooks in a paint tank. I also saw scrap machined castings that came back from the machine plant in the 60'S

[Mark F.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

GARY Not sure what or why it important to know when it was added to the JM but I build patterens for some of the foundries that cast them & watched them being painted on hooks in a paint tank. I also saw scrap machined castings that came back from the machine plant in the 60'S

Ken,

Do you know if Delco Moraine had their own foundry ?
or, did they receive the raw castings from a GM foundry and do the machining and assembly in their facilities ?

[Gary B.]

[Kenneth B.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Ken,

Do you know if Delco Moraine had their own foundry ?
or, did they receive the raw castings from a GM foundry and do the machining and assembly in their facilities ?

MARK
Believe some were cast at the GM foundry but not a Delco Moraine Foundry. i built the tooling for Midwest Foundry in Coldwater MI. They also cast master cylinders. Believe all castings were machined at the DM plant.

[Gary B.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

GARY
Not sure what or why it important to know when it was added to the JM but I build patterens for some of the foundries that cast them & watched them being painted on hooks in a paint tank. I also saw scrap machined castings that came back from the machine plant in the 60'S

Ken,


I think the question was motivated by the Lucas #635 rustproof specification on the engineering print and assumed observations of painted calipers on unrestored cars. Was the rustproofing material equivalent to black paint?





Gary

[Jack M.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Looking at various C2 & C3 Corvette assembly line photos, the brake calipers seem 'dark' in appearance.

1966 Convertible:
1966-Convertible-Body-Drop-(9-28-65d)-01.jpg
1966-Convertible-Body-Drop-(9-28-65d)-02.jpg


1966 Coupe:
1966-Coupe-Body-Drop-(9-28-65)-01.jpg
1966-Coupe-Body-Drop-(9-28-65)-02.jpg


1969 Coupe:
1969-Corvette-Assembly-Line-01.jpg
1969-Corvette-Assembly-Line-02.jpg


1977 Corvette:
1977-Corvette-Assembly-Plant-01.jpg
1977-Corvette-Assembly-Plant-02.jpg


1980 Corvettes:
1980_Build-03a.jpg
1980_Build-03b.jpg

1980_Build-07a.jpg
1980_Build-07b.jpg

[Joe L.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Ken,

Do you know if Delco Moraine had their own foundry ?
or, did they receive the raw castings from a GM foundry and do the machining and assembly in their facilities ?

Mark------


The 1965-66 calipers (546xxxxx castings) I believe were cast at a GM nodular iron foundry in Saginaw, MI. However, I am not certain of that.

The 1967-74 calipers (545xxxx castings) were cast at the GM foundry once located in Tilton (Danville), IL. This foundry produced malleable/ductile cast iron castings.

The 1975-82 calipers (547xxxxx castings) were cast at some non-GM foundry. I have no information on which or where. There is a foundry identification mark on these castings but I've not been able to "decode" it. These are gray iron castings

[Gary B.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Jack,

If this were a multiple choice test, I sure would select black paint as the answer.

Gary

[Joe L.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Jack,

If this were a multiple choice test, I sure would select black paint as the answer.

Gary

Gary------


Just to be clear, I do believe that most calipers, at least during the 1965-74 period were somehow "coated" in black. However, I am 100% sure that those on my original owner 1969 were not and were bare cast iron. If they were originally coated, then by the time I first had the wheels off the car (and, that's within the first 2 or 3 years ), then every trace of that coating had vanished. I highly doubt that would have occurred. So, while black coated calipers were likely the norm, there was at least one exception and, I expect, many more than one.

However, while my calipers were originally bare cast iron, they are not so now. Immediately after I had them sleeved about 40+ years ago, I painted them black. Why deviate from original? I HATE RUST.

[Mark F.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Mark------

The 1965-66 calipers (546xxxxx castings) I believe were cast at a GM nodular iron foundry in Saginaw, MI. However, I am not certain of that.

The 1967-74 calipers (545xxxx castings) were cast at the GM foundry once located in Tilton (Danville), IL. This foundry produced malleable/ductile cast iron castings.

The 1975-82 calipers (547xxxxx castings) were cast at some non-GM foundry. I have no information on which or where. There is a foundry identification mark on these castings but I've not been able to "decode" it. These are gray iron castings

https://www.youtube.com/watch?v=GPuX9WncHfE

Cast iron can be divided into five groups based on composition and metallurgical structure.

1. Grey cast iron
2. White cast iron
3. Malleable cast iron
4. Nodular cast iron
5. Compacted graphite cast iron.

My guess for the reasoning behind the changes in materials over that period of time is the 1^stst

[Jack M.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Just a couple more data points on caliper appearance... recent barn finds, with low mileage, during 1st wash.
Sorry... couldn't zoom in further, to clearly read the foundry ID markings.

1978 Corvette (293 Miles):
1978 Corvette Calipers (293 Miles).jpg


1982 Corvette (33 Miles):
1982 Corvette Calipers (33 Miles).jpg

[Kenneth B.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Mark------


The 1965-66 calipers (546xxxxx castings) I believe were cast at a GM nodular iron foundry in Saginaw, MI. However, I am not certain of that.

The 1967-74 calipers (545xxxx castings) were cast at the GM foundry once located in Tilton (Danville), IL. This foundry produced malleable/ductile cast iron castings.

The 1975-82 calipers (547xxxxx castings) were cast at some non-GM foundry. I have no information on which or where. There is a foundry identification mark on these castings but I've not been able to "decode" it. These are gray iron castings

You are right. We made tooling for Danville when I worked for another pattern shop.. Dont know if Defiance OHIO GM foundry also cast them. When i started my own shop in 1976 we made them for Coldwater foundry & they were dipped in black paint.

[Gary B.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

This has been a phenomenally interesting and educational thread. I want to thank everyone for their contributions. Hopefully future readers wanting to correctly detail their calipers for judging will benefit from it like I have.

Gary

[Joe L.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

My guess for the reasoning behind the changes in materials over that period of time is the 1^st caliper halve engineering and metallurgical designs were most conservative in terms of the “new technology” of using disk brakes on Corvettes (and other GM products). As warranty claims came in from those years - and quality research continued to develop, lower strength materials probably became more acceptable for production designs. Perhaps the thought was the 1^st materials were deemed to be “overkill” – I don’t know ? Again – speculation on my part.

PS - Do you have an image of the “foundry identification mark on these (’75-’82) castings but I've not been able to "decode" it ?"

.

Mark------


I have surmised EXACTLY the same thing for years.

Here are some photos of 547xxxx castings with foundry marks. Note that there are two different foundry marks (one "triangular" and the other "hourglass within a square". I assume this means that at least 2 different outside foundries cast these 547xxxx caliper halves.

DSCN0805.jpgDSCN0808.jpgDSCN0818.jpgDSCN0812.jpg


Here is an example of the 545xxxx caliper half casting. Note the prominent "D" and Central Foundry "wagon wheel". The Danville foundry was very consistent with emplacing their specific foundry identification mark on castings they produced. Other GM foundries were not so good. Some emplaced the "wagon wheel" but without reference to the specific foundry. Some did nothing. The worst was Defiance, OH. I have never seen a Defiance casting with a foundry mark (and I know it was definitely not "D"). In fact, I went on a VERY MUCH appreciated private tour of the Defiance gray iron foundry once-upon-a-time. Even the supervisors that graciously took me around and answered my questions didn't know what a foundry identification mark was, let alone any used for that foundry.

DSCN0809.jpg

[Mark F.]

Re: Unpainted, machined areas on 65/66 brake calipers; A questionable area

Mark------I have surmised EXACTLY the same thing for years. Here are some photos of 547xxxx castings with foundry marks. Note that there are two different foundry marks (one "triangular" and the other "hourglass within a square". I assume this means that at least 2 different outside foundries cast these 547xxxx caliper halves.....Here is an example of the 545xxxx caliper half casting. Note the prominent "D" and Central Foundry "wagon wheel". The Danville foundry was very consistent with emplacing their specific foundry identification mark on castings they produced. Other GM foundries were not so good. Some emplaced the "wagon wheel" but without reference to the specific foundry. Some did nothing. The worst was Defiance, OH. I have never seen a Defiance casting with a foundry mark (and I know it was definitely not "D"). In fact, I went on a VERY MUCH appreciated private tour of the Defiance gray iron foundry once-upon-a-time. Even the supervisors that graciously took me around and answered my questions didn't know what a foundry identification mark was, let alone any used for that foundry.

Hi Joe,

As usual, your replies are exceptional !

What I have also found was the guys and gals doing the work on the line couldn't always express those things we want to know today - because they were not important to them when they were on the line punching out XXX castings per hour or per day

What I also know is at least one line worker surprised me when he knew exactly what I was doing (Industrial Hygiene air sampling at the cope and drag separation station in the bowels of a Casting Plant) and out of the blue, he said to me "What kind of filter are you using there ? Momentarily stunned, I said "as a matter of fact it's a Gelman 0.45 micron millipore filter" and he said - "Oh yeah, that's what we used when I was in the Air Force to check for debris in aircraft fuel tanks before take off...

I have always treasured that experience and have never forgotten about who ends up "on the line"....and what their qualifications are (were) from previous training and experience...