C3 brake caliper date codes

[Brandon Corvette]

I'd like to know which if any of the brake calipers on my largely original 1972 LT-1 convertible could be original. Below are the numbers taken off of them. Please help by decoding them or directing me to a website or other resource so I can decode them myself. Thanks!

LF outside of caliper: Delco Morraine, 5473786, 8202
LF inside of caliper: 5473786, 7157

LR outside of caliper: Delco Morraine, 5473807, R3
LR inside of caliper: 5473806, 3386

RF inside of caliper: 5473795, 9247

RR inside of caliper: 5473806, 3063

[Joe L.]

Re: C3 brake caliper date codes

Brandon-----

If you had asked about any other year Corvette, it would be possible to give you a more definitive answer. GM changed the caliper casting numbers sometime during the 72-73 period. Primarily, this reflected a change in the caliper material, but it also reflected certain design changes due to the revised caliper material. Anyway, I believe that most, if not all, 1972's were built with calipers with casting number prefix of "545". However, it's possible that some 72's, especially late cars, may have been built with the "547" series caliper castings. I think that late 1972 and/or 1973 was a "transition period" when castings were being produced at 2 different foundries, with the production at one scaling down and production at the other scaling up. Actually, I really believe that the transition began in late 1973, but I would not rule out that it started as early as late 1972.

As far as the "date codes" go, they're fairly meaningless. If they represent a date code, at all, it's a coding system that no one I know of has figured out yet. For example, and in your case, let's assume that it's a julian style date coding system often used by Delco-Moraine. Let's also assume that the FIRST digit represents a year. That would mean that your first caliper was made 1978 (or 1988 for SERVICE). The second caliper would have been made in 1977 (or, 1987 for SERVICE). The third made in 1973 (or, 1983 for SERVICE). The fourth made in 1979 (or, 1989 for SERVICE) and the fifth made in 1973 (or, 1983 for SERVICE). The problem with this is that the third caliper would then have to have been manufactured on the 386th day of 1973 or 1983. Of course, that's impossible. So, that decredibilizes the whole theory that this was the coding system

Let's say that it's a julian system with the LAST character of the series representing the year. That would mean that the first caliper was made in 1972 (or, 1982 for SERVICE). The second caliper was made in 1977 (or 1987 for SERVICE). The third caliper made in 1976 (or 1986 for SERVICE). The fourth made in 1977 (or, 1987 for SERVICE). The fifth made in 1973 (or, 1983 for SERVICE). The problem with this is that the first caliper would have to have been made on the 820th day of 1972 or 1982 and the second caliper made on the 715th day of 1977 or 1987. Obviously, those are impossibilities. So, that decredibilizes this theory of how the coding worked.

[Brandon Aalunn]

Re: C3 brake caliper date codes

Wow, thanks Joe. Please note that this profile of mine was deleted, so I recreated it (using a legitimate last name) and posted the same question on 6/27 (a dupe). All of my calipers begin with "547". I was told the "date code" was on the inside/back half of the caliper near the mounting bolts, but these numbers are inconsistent: 7157, 3386, 9247, 3063. I'm asking because I want to know if they should be rebuilt (if original) or replaced (if not original). The car is rarely driven, so I'm considering stainless sleeves and o-rings.