64 Z-06

[Dan H.]

Re: 64 Z-06

Matt, that's a J65 set up, nice.

[Matt L.]

Re: 64 Z-06

Matt, that's a J65 set up, nice.

Are you sure?? It does not have the ventilated backing plates or finned drums on this. I believe these have never been tampered with as the car sat since 1983. I bought off my health ailing uncle in law in June and I'm trying to find out everything I can about this car.
Thanks, Matt

[Matt L.]

Re: 64 Z-06

Are you sure?? It does not have the ventilated backing plates or finned drums on this. I believe these have never been tampered with as the car sat since 1983. I bought off my health ailing uncle in law in June and I'm trying to find out everything I can about this car.
Thanks, Matt

Ok got it, the J56 had the ventilated backing plates and finned drums.
The J65 like mine has the sintered metallic and heavier brake package with power booster.
Great info.

[Doug L.]

Re: 64 Z-06

So to try to sort this out a little:

-The J50 option was sintered metalic shoes with vacuum booster, non-finned drums and standard back plate?
-The J-56 option was sintered metalic shoes with vacuum booster, dual master cylinder, non-finned drums and standard back plate?
-The J-65 option was sintered metalic shoes without vacuum booster (unless J50 also ordered), finned drums and air scoop on the back plate?

Duke, you mentioned heat-treated springs. Are you referring to the springs mounted on the back plate? When I bought my car the front drums had springs of approximately 3/8" diameter completely around the outside of the brake drum at the flange near the back plate. I never knew if those springs were OEM or what they were for.

I suppose the only place the codes appeared was on the window sticker, if there. Here is my invoice.

Doug

[Dan H.]

Re: 64 Z-06

So to try to sort this out a little:

-The J50 option was sintered metalic shoes with vacuum booster, non-finned drums and standard back plate?
-The J-56 option was sintered metalic shoes with vacuum booster, dual master cylinder, non-finned drums and standard back plate?
-The J-65 option was sintered metalic shoes without vacuum booster (unless J50 also ordered), finned drums and air scoop on the back plate?

Duke, you mentioned heat-treated springs. Are you referring to the springs mounted on the back plate? When I bought my car the front drums had springs of approximately 3/8" diameter completely around the outside of the brake drum at the flange near the back plate. I never knew if those springs were OEM or what they were for.

I suppose the only place the codes appeared was on the window sticker, if there. Here is my invoice.

Doug

Doug, all the info above is wrong.
J50 is for a vacuum booster only
J56 has finned drums, dual MC, booster, vented backing plates, HD shoes.
J65 has power brake booster, sintered metallic linings and beefed up non finned drums, standard backing plates.

You invoice looks like J65 for 64 model year.
Can I get a scan of you invoice for my Malcohm Konner 64? Thanks,
Dan

[Matt L.]

Re: 64 Z-06

I too have the springs on my J65 brakes, factory original equiptment. Not sure what they do, maybe dampen the brake noise??

But I am confused about the invoice Doug produced as far as his serial # 7060 of his car from March 16, 1964.
My car came off the line in January 6, 1964 with serial # 8307. How could his be 1247 cars before mine, be a special order and not come out until March??
Maybe someone could enlighten me??
Thanks, Matt

[Dan H.]

Re: 64 Z-06

Matt, that was when it was sold, not made. Must have been around for awhile before sale.

[Matt L.]

Re: 64 Z-06

Dan,
The brake drums are not finned though. I read the book The complete restoration guide ..... that said J65 had finned drums but not ventilated backing plates. Is that incorrect?
I was under the impression mine were only J50 vacuum booster. That woud be better to hear that I do have J65, right?
thanks, Matt

[Dan H.]

Re: 64 Z-06

Matt, your brakes are the J65 sintered metallic which includes the booster and special non finned drums, thicker webs on the front drums with the external spring, no spring on rear drums. Fronts marked with an 'X' and rears with an 'L'.
Dan

[Duke W.]

Re: 64 Z-06

I checked the 1964 AMA spec package there is a clear indication that J-65 included a vacuum booster, which I was not aware of, but that was not the case in 1963. For a long time I was under the impression that J-50 power booster was not available with J-65 in 1963, but apparently it was.

My SWC has J-65, but not J-50. I recall when hot lapping Kent back in the day that the brakes became very sensitive - almost like power brakes after temperatures had stabilized, and I would think they would be way too senstive with a power booster under racing conditions.

For normal use the power booster would have been useful - especially those first couple of stops in the morning when the lining coefficient was low and it took a lot of pedal effort to make even a moderate stop. That was something that I just got used to.

The unique heat treated springs for J-65 refers to the pullback springs, not the squeak damping spring on the outside of the drum. Up at least through the mid-seventies, GM offered a spring package that included all internal springs, and metallic brakes was a different number than base brakes due to the different pull back springs. I recall that the base/metallic pull back springs were differentiated by color, but I don't recall the details.

It's always been my contention that J-65 brakes will haul down a Corvette from any speed as well as disk brakes, however given the self-energizing characteristics of drums and the wide variation in lining friction coefficient (It increases with lining temperature) pedal effort versus deceleration rate is highly non-linear compared to the disk system, so J-65 requires considerable more skill to brake at the limit of adhesion without locking up one or more wheels.

The J-65 linings are very long lived - typically well over 100K miles in normal road service, but when the linings are worn out, so are the drums. I recall a couple of recent cases where the original J-65 linings were still in place and no more than half worn, but hydraulic problems had developed. My advice to the owners was to disassemble the system, carefully marking the position of each drum and lining, clean everything up, rebuild the hydraulic components and install everything back in the original position.

Duke

[Rex T.]

Re: 64 Z-06

So.....................lots of good discussion here. I wonder exactly when the J-56 brakes could be ordered on a 64 Corvette? Based on documents presented here in this thread, it appears that they "could " have been ordered in Dec. 1963. However, in Noland Adams' book The Complete Corvette Restoration & Technical Guide - VOL. 2, 1963 through 1967, page 221 under the explanation of option J-56, and I quote.................."Includes finned brake drums with built-in cooling fans, front brake air scoops, with dual circuit master cylinder and special sintered-metallic linings (available only when 375 H.P. engine, 4-speed transmission and positraction rear axle are ordered)............ Available late January 1964.

Anyone have any hard facts on exactly WHEN it became available?

On another note....................I have heard that ONE 64 with 365 HP engine was was built with J-56 brakes. I didn't think that combination was possible.

[Jack C.]

Re: 64 Z-06

I have a copy of the Car Life August 1964 with the 64 and the Cobra on the cover if your're interested Rex?

Been a while since I was here, so please bear with me.

OK..................don't everybody jump on me at once!! I know GM never offered the Z-06 option in 64 (well actually they did, VERY early in the year, and for only a short time). However, beginning in late January or early February 1964, the same Z-06 brake package became available for 64 Corvettes as option J-56, offered only with other "mandatory" options L-84 fuel injection and F-40 heavy duty suspension. The J-56 brake option consisted of the heavy duty sintered metallic brake linings with huge finned drums and vented backing plates.................................ALL of which were leftover from the Z-06 package in 1963.

Now...................to the reason for this post. Fortunately, and with a bit of luck, I have one of these 64 J-56 Corvettes and would like to converse with other 64 J-56 owners. However, this may be somewhat difficult as Chevrolet made only 29 such cars in 64 out of a total production of 22,229. This low production number, coupled with the fact that these cars are now 45 years old and the probability of all 29 surviving being extremely unlikely, my chances of finding someone on the forum who has one is slim. But, you never know until you try. So, with all this said......................are there any other 64 J-56 Corvette owners out there?

Anxiously waiting to hear from you!!!

Thanks,
Rex

[Rex T.]

Re: 64 Z-06

Thanks Jack. I have that issue too.

[Jack C.]

Re: 64 Z-06

OK Rex. If anyone else has a 64 Z-06. Let me know, n/c for the magazine, just send me your mailing info.

Thanks Jack. I have that issue too.

[Rex T.]

Re: 64 Z-06

I would still like to determine when the firts J-56 car was built. I have compiled a list of 11 of the 29 cars and thus far, mine is the earliest one,............... built in Feb. 1964. Could mine be the first one???????????????