Z07 75 Vette

[William T.]

I posted some time ago regarding my 75. A number of you were very helpful and I can't thank you enough. I did confirm that my car has the correct part #'s on the brackets and that their general condition is the same as the rest of the chassis so not likely to be faked. I do not the correct calipers. Do any of you have a picture of the caliper. It's my understanding that the correct caliper has dual pins but they do not look like the single pin. They look more like a cotter pin. Also, the picture I've seen shows the top of the caliper does not have the "hump" in the middle where the single pin goes through.

Any help is as always appreciated.

Bill

[Joe L.]

Re: Z07 75 Vette

I posted some time ago regarding my 75. A number of you were very helpful and I can't thank you enough. I did confirm that my car has the correct part #'s on the brackets and that their general condition is the same as the rest of the chassis so not likely to be faked. I do not the correct calipers. Do any of you have a picture of the caliper. It's my understanding that the correct caliper has dual pins but they do not look like the single pin. They look more like a cotter pin. Also, the picture I've seen shows the top of the caliper does not have the "hump" in the middle where the single pin goes through.

Any help is as always appreciated.

Bill

Bill----

The dual pin, J-56 calipers apply to the fronts only. The rear calipers are the same as non-J-56. The front J-56 calipers have the same casting numbers and are the same casting as the non-J-56. Their manufacture involved only the machining off of the pad pin bosses (humps, as you call them) and the drilling of the holes for the pins used to retain the J-56 pads. It is VERY easy to make a set of front J-56 calipers from a set of standard calipers (but, it's impossible to make a set of standard calipers from a set of J-56) because that's exactly how Delco-Moraine did it.

The other difference involved the pistons. These were different from standard brakes inasmuch as they were an aluminum piston with a thick Pyroceram insulator attached to the front. Standard pistons were all aluminum.

The J-56 brake pads were also different. The fronts had a "curved over" top edge which gave them significant extra rigidity. This was also the reason for the difference in the pin configuration. All 1975 J-56 used front pads with inconel backing plates. The rear brake pads used standard configuration backing plates but the friction material compound was different.

[William T.]

Re: Z07 75 Vette

Joe,

Thanks for the reply. I shop in I believe is S. Jersey told me they had a pair and I wanted to be sure they were original. He is sending me photo's by snail mail so at least I have an idea what they should look like.

Thanks again.

[Joe L.]

Re: Z07 75 Vette

Joe,

Thanks for the reply. I shop in I believe is S. Jersey told me they had a pair and I wanted to be sure they were original. He is sending me photo's by snail mail so at least I have an idea what they should look like.

Thanks again.

William----


I would not pay any sort of significant premium for "original" J-56 calipers. For one thing, you have no way of knowing if they are really original. Secondly, as I mentioned, a set of standard calipers can be converted to J-56 configuration in exactly the same manner that Delco-Moraine did it. Once converted, they will be indistinguishable from originals.

By the way, 1975 used the so-called "third design" calipers (actually, as far as configuration goes, these were very slightly modified 2nd design). So, the caliper half casting numbers will be as follows:

front-----5473795, 5473796

rear------5473807, 5473808

These are the easiest, by far, of all caliper castings to find. However, original J-56 front calipers with these casting numbers are not easy to find. Only 236 Corvettes were ever built that originally used them. As I say, though, you can easily make up a set of these from standard calipers with these casting numbers.