Well, I have to admit I wrote my diatribe without bothering to check the
manual, but I assure you there is a minimum thickness specification
somewhere, as they are furnished to brake shops by the brake lathe
manufacturers each year when the new models come out. I don't have my 68
manual here at home, but I will check it tomorrow - (not that I doubt your
statement).
On manual I happen to have here, it is on the "specifications" page, in the
brake section - for 1981 this is on page 5-44, and I quote "Minimum
thickness 0.940" (The new thickness is 1.000").
I quote further: "Note: All rotors (disc) will show markings of minimum
allowable thickness cast on an un-machined surface."
With regard to Drum brakes, I quote the following note: "All drums will show
markings of maximum allowable diameter." For 1981, this is on page 5-14.
For 1972, the above information is on pages 5-57 and 5-11, respectively, and
the same "notes" are there also. If it's not in the 68 manual, someone
should be taken to the woodshed!
Dick Benjamin
----- Original Message -----
From: D. Dardalis <dardal@xxxxxxxxxxxxxxx>
To: <mailing-list@xxxxxxxxxxxxxxxx>
Sent: Thursday, April 18, 2002 10:15 AM
Subject: IML: minimum rotor thickness?
> At 09:24 AM 4/18/2002 -0700, you wrote:
> >There is a minimum thickness for safe operation, turning them below that
> >specific thickness risks brake failure due to fade and perhaps warping.
The
> >minimum safe thickness will be in the FSM, and is usually cast into the
> >rotor/drum somewhere to warn the brake shop. No professional brake shop
> >will turn a drum or rotor below that minimum, lest he open himself up to
a
> >monstrous liability/lawsuit, and, at least in CA, lose his garage
keeper's
> >license.
>
> Dick, I was looking at the 68 repair manual trying to find the minimum
> thickness. I may be wrong, but I think they did not list a minimum
> thickness. Instead, they just said that rotors should never be turned and
> machined! They assumed that nobody will machine them, so they did not
> publish a minimum thickness, or so it seems.
>
> D^2
>
>
>
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