I decided to dive into a brake job tonight and began the teardown of the fronts when I noticed that the brake shoes are metallic and the brake cylinder is marked 1-3/16-inch on the side in raised metal casting. I learned that my 62 is an ex-fuelie over Christmas and I am now wondering if this car had the big brake option. Any advice or comments? Anything else to look at while it is apart? Thanks in advance.
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Re: 62 Big Brake Option?
There were two brake options in the drum brake era. First was RPO 686, beginning in '59 IIRC, which substitued metallic linings for standard organic linings. The drum castings were the same as base, but had a finer finish on the friction surface, Also, the retraction springs were "special" with higher heat capability.
The HD brakes are easily identifiable by their fined drums.
The metallic brake option carried over to the 63-64 era as RPO J-65.
Little is understood about 686/J-65 since they can only be identified by removing a drum, which is not part of the NCRS judging process.
My experience with J-65s on my SWC is that they will not fade, but become senstive like power brakes when heated to extreme by race track hot lapping. They are also relatively ineffective when cold and need a couple of stops in the morning to heat up.
The linings are very long lived - well over 100K miles of normal street driving, but when the linings are worn out, the drums are usually worn out too.
If the shoes and drums are still serviceable (drums worn less than .090"), I would recommend reusing them (with a good cleaning) with new or rebuilt wheel cylinders.
A good alternative to the metallic linings, which are long gone, is to have the shoes relined with carbon-metallic linings by Carbotech Engineering:
www.carbotecheng.com
with new or turned used drums.
Duke -
Re: 62 Big Brake Option?
Duke,
Thanks for your response. While you were responding I was digging through my Noland Adams Restoration Book and found RPO 686. I believe this is what I have as I do not have the finned brake drums. The brake cylinders are called out as being 1.1875 inches in bore diameter. I believe this to be what I have. Thanks.Comment
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Re: 62 Big Brake Option?
are the backing plates screened and does it have the fast steering adaptor? also look at front lower valence panel==are there a pair of rectangular ducts bonded to the backs side of the valence? if yes to all of above, it may have been a big brake/hd susp 62.however, from your posts, its probably a sintered metallic brake lined 62. good luck, mikeComment
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Re: 62 Big Brake Option?
I believe the standard brakes had the 1-3/16" cylinders and the HD brakes were 1-1/8". The service replacements are 1-1/8" as the 1-3/16" have become scarce.Comment
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Re: 62 Big Brake Option?
I seem to recall something about the color of the brake shoe springs being an issue with this option. Dale Pearman did an article in The Restorer about this, if memory serves.Comment
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Re: 62 Big Brake Option?
The special return springs used with 686/J-65 are painted a differnt color than the base springs, but I don't recall the specific colors. IIRC the 686/J-65 springs have the same geometry, but are heat treated to a higher hardness to be more heat resistant.
For those cars that have the 686/J-65 option, even if they have the original springs, it's likely the paint burned off years ago, but careful cleaning might show some recognizable remnants.
Few have the original or replacement segmented metallic lining shoes.
DukeComment
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Re: 62 Big Brake Option?
In the extensive article I did in the Restorer some years ago, I pointed out that the standard and RPO686 brakes both had the 1 3/16 fronts. The return springs for 686 are considerably larger in diameter than the standard ones, and they are pink and yellow in color. That should help determine whether or not you have 686 or not--there are no other telltale signs besides the shoes, the springs, and the fineness of the finish on the drums.
Mike ErnstComment
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DUKE: Relining Metallic Shoes
Duke
Any idea what Carbotech charges to do the segmented metallic shoes on a 63? Their web site had no clue, or I missed it. I have an extra used 63-64 set with a couple of segemets broken off.
Geoffrey CoenenComment
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Re: DUKE: Relining Metallic Shoes
I talked to the owner a few years ago and he is an experienced J-65 hand. I don't think the carbon metallic linings are segmented, but he said they have the fade resistance of the metallics without the sensitivity.
My J-65s will probably never wear out, but if I had to get new linings, I would go with the carbon metallics from Carbotech Engr.
Suggest you give them a call.
DukeComment
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Re: 62 Big Brake Option?
All C1's had the raised numbers cast on the wheel cylinders original and would be original were the replacements don't.Comment
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