1966 Brakes

[Greg T.]

I'm doing an NCRS resto on my 66 coupe. When I checked the brake caliper casting numbers several pieces did not match the NCRS manual. When I went to look for some the brake vendors were all telling me that the casting numbers I wanted were not for a 66. They offer a first design brake kit (using different casting numbers from 66 manual) which is supposed to be for 65s and 66s. They all swear these are the proper brakes. They used phenolic insulators and internal guides for the pistons. Does anyone know whats up?

[Joe L.]

Re: 1966 Brakes

Greg-----

ALL original 65-66 Corvettes (except 316 1965 disc brake delete cars) and very early 1967 Corvettes used "1st design" calipers. These calipers used pistons with guide pins on the rear and caliper half castings with cast-in piston guides into which the piston guide pins fit. ALL first design calipers use insulated pistons with a Pyroceram insulator attached to the face of the piston by a central phillips head screw. These insulators are a dark brown color and are about 5/16" thick. Many "1st design" calipers have been converted to "2nd design" by brake rebuilders in which case the piston guides are machined out of the caliper halves and 2nd design non-guided pistons are used. 2nd design pistons, except for those used for J-56 applications, have no insulators.

ALL ORIGINAL first design calipers have casting numbers which begin with "546". NO calipers for ORIGINAL 1st design units used ANY OTHER CASTING NUMBER PREFIX. So, if you have a set of calipers with 8 caliper halves, all with casting numbers beginning with "546", then you have a set of 1st design calipers as used on all 65-66 and very early 1967 Corvettes. Of course, the calipers may or may not have been otherwise converted to 2nd design configuration by machining out of the piston guides. As I say, most have been so-converted. Thewre is no way to convert them back to 1st design and use the 1st design type pistons: once they're converted to 2nd design, it's for good.

It IS possible to have 1st design calipers (with cast-in piston guides) which have other caliper casting numbers (i.e. "545" or "547"). However, these are later SERVICE 1st design calipers. These were NEVER, EVER originally used on a 1965-66 Corvette or an early 1967 Corvette. Many caliper halves were once sold in SERVICE and those comprise a significant fraction of the rebuilt castings out there. That's because prior to about 1975, stainless steel sleeved calipers did not exist. The only way to repair a Corvette caliper was to replace any caliper halves which suffered from damaged bores. MANY were thus replaced. Even after 1975 the word did not get out right away about stainless sleeved units and many Corvettes were repaired with new caliper halves for many more years. When the parts were available, that's just about the only way that Chevrolet dealer service departments repaired Corvette calipers.