Is there a good tech article on 65-82 brakes?

[Patrick H.]

I happened to stop at my "driver car" mechanic today to ask for a favor. While I was there his son (who works for him) had a '77 Corvette apart with the front spindle off and all the calipers removed. He said that the lady who owned it was thinking about replacing the calipers (they were trashed; it would be a waste to use them and I did mention that) and wanted new rotors. I tried to explain to him that removing the rotors and installing new ones with no further truing would cause other issues like air pumping, but he thought I was nuts. I explained how the fronts should be measured and if they meet spec then turned while still riveted to the hub. He said that the front rotors "had to be warped after sitting for 15 years."

Frankly I thought that a few minutes with a 3M kit and they'd look fine. No signficant pits at all, just surface rust.

Anyway, he walked away as I attempted to explain politely that the Corvette system was different, telling me he "always did them this way." I was hoping that one of you might recall an article in the Restorer or another magazine that explains runout, air pumping, etc as I'd like to get him a copy.

Thanks for any help you can provide.

Patrick

[Jerry G.]

Re: Is there a good tech article on 65-82 brakes?

Zora wrote an SAE ( society of automotive engineers) technical report on the 65 disc brake system. It was really pretty interesting to read. It was done in 64 and I've seen it on-line. Not sure where.

[Vinnie P.]

Re: Is there a good tech article on 65-82 brakes?

Patrick...check your email...recently received an article for an upcoming issue of The Restorer reference just what you're talking about...however it hasn't been edited or even read thoroughly, but it may help.

[John H.]

Re: Is there a good tech article on 65-82 brakes?

Patrick -

Try this link, parts 12 & 13:

http://www.idavette.net/hib/vette_bbfh.htm

[Duke W.]

Re: Is there a good tech article on 65-82 brakes?

Zora wrote an SAE ( society of automotive engineers) technical report on the 65 disc brake system. It was really pretty interesting to read. It was done in 64 and I've seen it on-line. Not sure where.

I have the paper, and as you say, it's an excellent overview of the disk brake system, but it doesn't get down to a level of detail that Patrick needs.

As far as runout is concerned, it can be measured on the car with a dial indicator, but most "mechanics" won't bother, assuming they even have a dial indicator.

Most of the rotors on my cars are scored silly due to hot lapping them on racetracks, but they have no runout and are above minimum thickness, so I just replace pads when they wear out, but there's a problem with this for "normal" people.

Most mechanics want to turn or replace rotors because new pads and new rotor surfaces with break in very quickly without any special effort on the part of the driver - just a hundred miles or so of "normal" road driving.

New pads on scored rotors require a thoughful break-in, and I run a 200-300 mile schedule of road driving where I start out with very light braking and gradually increase brake system load, usually finished off on a twisty road that requires heavy braking before the next corner.

Only this kind of concerted effort will allow fresh pads to seat on scored rotors. If you immediately start out with heavy braking - like a track event - before the pads are seated, many pad materials will never seat, the brakes will never achieve full effectiveness, and the pads will wear quickly.

Duke

[Patrick H.]

Re: Is there a good tech article on 65-82 brakes?

Thanks guys.

I know that some excellent posts have shown up here on the forum, but finding them isn't easy either.

Patrick

[Jim T.]

Re: Is there a good tech article on 65-82 brakes?

Patrick my experience with my original owner 68, recently rebuilt the calipers, repacked the wheel bearings, and still using the original factory installed discs. Almost 100k on them, no warping and need no preping
My 1970 original owner still has its factory installed front discs. 160K miles. No warping, my Corvette's discs are not like the thin el cheap o's that come on some cars.

[Alan S.]

Re: Is there a good tech article on 65-82 brakes?

Hi Patrick,
The SAE report that Zora Duntov and Arnold Brown wrote, and Jerry and Duke mention, is in THE RESTORER Volume 6, Number 2, Fall 1979.
If you'd like to have it but don't find access let me know and I'll gladly send it to you.
Just the design parameters and objectives by themselves are interesting. 2 of the illustrative photos are from a GS car.
Regards,
Alan