'67 J56 calipers

[William F.]

Anyone have suggestion of where to purchase a set of dated J56 front calipers for my '67 built in Feb. '67? Car came with big brake option but a previous owner replaced the 4 pin calipers with standard calipers, I suppose, due to high cost of the special pads required for J56. Car has the proportioning valve intact.Any idea of cost for calipers?
Thanks in advance

[Keith G.]

Re: '67 J56 calipers

If you are going to any ncrs shows, make sure that you have the heavy arms that hold the calipers, the arms will work on the single pin caliper or the 2 pin caliper but the j56 cars had a heavier arms.

[Richard F.]

Re: '67 J56 calipers

It amazes me to think of a time when an owner would give up J56 calipers due to the cost of replacement pads. It is very understandable, but also sad. Even the reinforcement pieces (dogbones) command a high price today.

[Dick W.]

Re: '67 J56 calipers

Very easy to convert single pin to two pin calipers. Just mill the pin boss off the top and use the dual pin pads as a guide to drill your holes

[Michael H.]

Re: '67 J56 calipers

Caliper modification for HD brake pads.

[Joe L.]

Re: '67 J56 calipers

Very easy to convert single pin to two pin calipers. Just mill the pin boss off the top and use the dual pin pads as a guide to drill your holes

Dick-----


Yup, and that's exactly how GM did it. Any standard caliper can be easily converted to J-56. However, the converse cannot be accomplished----a J-56 caliper cannot be converted to standard.

Early 1967 with J-56 used the 1st design calipers and pistons. These pistons used the "thin" Pyroceram insulators.

Late 1967 with J-56 used 2nd design calipers and pistons. These pistons used the "thick" Pyroceram insulators.

[William F.]

Re: '67 J56 calipers

Thanks. I'm already aware of how to modify a standard caliper for use with HD pads, but what about judging? Aren't casting numbers and dates present and judged? What kind of a deduct would I get if I used modified calipers with wrong casting nos. and wrong dates? I have build sheet proving car came with J56.
Thanks again

[William F.]

Re: '67 J56 calipers

Joe,
After posting my question about casting nos./dates as related to judging, I got the answer from one of your previous posts to another member about same thing.Glad we got the "similar threads" part of the web site working again. However, I'm confused about "pistons being hard to find." If I just modify my regular calipers for the 2 pin setup and pistons in these calipers are in good shape, do I need to worry about calipers? Won't ones already in place work?
Thanks

[Dick W.]

Re: '67 J56 calipers

Unless you are racing the car, or real particular about having everything exactl like it left the factory, the piston issue doesn't make any difference.

If you don't know what the pistons look like, I think that I have one set left and can make photos

[Joe L.]

Re: '67 J56 calipers

Joe,
After posting my question about casting nos./dates as related to judging, I got the answer from one of your previous posts to another member about same thing.Glad we got the "similar threads" part of the web site working again. However, I'm confused about "pistons being hard to find." If I just modify my regular calipers for the 2 pin setup and pistons in these calipers are in good shape, do I need to worry about calipers? Won't ones already in place work?
Thanks

William------


Just as Dick mentions, you don't really need to change the pistons unless you want even unseen things to be "correct". You can use the existing pistons if they are OK for re-use. Even if they are not, you can replace with standard pistons at a FAR lesser expense than the insulated type assuming that your car uses 2nd design calipers and pistons. 1st design calipers used the same insulated pistons for either standard or J-56. 2nd design uses non-insulated pistons for standard and insulated pistons (but a different type than 1st design) for J-56. Many 1st design calipers (casting numbers 546xxxx) have been converted to 2nd design "somewhere along the way". If so, 1st design pistons cannot be used in a converted caliper.

For street use you don't need insulated pistons.

[Wayne M.]

Re: '67 J56 calipers

..... 1st design calipers used the same insulated pistons for either standard or J-56. 2nd design uses non-insulated pistons for standard and insulated pistons (but a different type than 1st design) for J-56. Many 1st design calipers (casting numbers 546xxxx) have been converted to 2nd design "somewhere along the way". If so, 1st design pistons cannot be used in a converted caliper. ...

Has it been determined the approximate break point between standard 1st and second design 1967 pistons ? William's February car is about half way through 1967 MY production.

Are these the 2nd design '67 & '68-9 J56 pistons and insulators ? (Pic from eBay, a while ago). Hope this works -- its a .bmp file.

[Joe L.]

Re: '67 J56 calipers

Has it been determined the approximate break point between standard 1st and second design 1967 pistons ? William's February car is about half way through 1967 MY production.

Are these the 2nd design '67 & '68-9 J56 pistons and insulators ? (Pic from eBay, a while ago). Hope this works -- its a .bmp file.

Wayne-----


Yes, these are 2nd design J-56 pistons and insulators.

I don't know when the change occurred for the 1967 model year from 1st to 2nd design.

[Robert K.]

Re: '67 J56 calipers

I believe there is a difference.....THe J56 brake setup was specifically designed for racing and as such operate much better under hi- temperature environments, like racing. For street use, where temperatures on the pads and assembly do not reach that seen when subjected to racing conditions, they do not perform nearly as well and the stopping distance is much different, I.e longer. This setup works great in those (racing) conditions.

[Joe L.]

Re: '67 J56 calipers

I believe there is a difference.....THe J56 brake setup was specifically designed for racing and as such operate much better under hi- temperature environments, like racing. For street use, where temperatures on the pads and assembly do not reach that seen when subjected to racing conditions, they do not perform nearly as well and the stopping distance is much different, I.e longer. This setup works great in those (racing) conditions.

Robert-----


The main factor which affects the characteristics you described is the pad friction material. J-56 did use a completely different, semi-metallic friction material compound. This was designed for racing applications and could produce inferior performance on the street.

As far as the rest of the J-56 set-up is concerned, it would not compromise street performance in any way. As mentioned, the calipers were essentially the same. The dual pin design was used to accommodate the backing plate configuration of the special racing pads. The J-56 insulated pistons would provide no real advantage on the street but they present no disadvantage, either----just increased cost with no commensurate benefits. The special cast caliper supports also provide no real advantage on the street but create no compromise to street brake performance.

If one does set-up their car with a J-56 brake installation, there's not too much concern that they'll use the original J-56 pads. These pads are long-since GM discontinued and difficult to find. If they foolishly decide to go for some other sort of racing pad for street use, they do so at their own peril.

[Dan P.]

Re: '67 J56 calipers

Funny the original owner spent the money to convert J56 to standard calipers. This is how the previous owner of my '70 ZR1 solved the problem when he couldn't locate J56 pads at the local parts store back in the mid '80's...
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