Date: Tue, 17 Aug 2004 07:25:49 -0400
Reply-To: vw4x4@FYI.NET
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Eric Zeno <vw4x4@FYI.NET>
Subject: Re: Rotor thoughts
In-Reply-To: <4DFA4DF6-EFC0-11D8-B9AA-000A95D4810A@mac.com>
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"a picture would resolve that issue very easily"
You got it!
http://www.fyi.net/~vw4x4/in1.jpg
http://www.fyi.net/~vw4x4/in2.jpg
Here is 2 pictures of the inner side of the rotors
http://www.fyi.net/~vw4x4/out1.jpg
Here is the outer side. You can see they are not as bad
but still have had rust biuld up on them.
http://www.fyi.net/~vw4x4/pads1.jpg
Here is the pads in not particular order. Look close
you can see there is plenty of meat on them.
As you stated below in more techincal terms
than I want to understand, I thing the rotors are the problem.
Unfortuneately I've gotta to get to work.....
ERic
Kim Brennan wrote:
> That's not true. You don't have to do a chemical analysis of the metal
> (which actually will likely give you very little information of value
> anyway). Of far more importance when dealing with metal is the
> crystalline structure.
>
> The crystal structure can reveal flaws that will lead to failure. It
> can reveal nonhomogenous composition. Depending on the nature of the
> material crystal structure can sometimes be revealed by patterns.
> Analysis of meteorites, for example is done by polishing the surface
> and then etching with acid. In industrial applications spectroscopic
> imaging tends to be used. Rotors being cast, should have a crystal
> lattice that is revealable. Forged metals tend to reduce the size of
> the crystals (removing the gaps in the crystalline structure, and
> improving the strength of the forged material.)
>
> You have continued to claim that your rotors are "bad", without
> describing that nature of the problem (other than "rust", which is
> perfectly normal on rotors.) Are the rotors warped? Are they cracked?
> Are they out of balance? If so how did you determine they were out of
> balance? Wear patterns can often times be extremely illuminating, hence
> why pictures are valuable.
>
> While state inspections vary, most places are concerned with.1) Do the
> brakes work? 2) Are the materials within tolerances? 3) And are the
> materials up to the standards of the day (not necessarily TODAY's
> standards, but the standards of the original manufacture date of the
> vehicle.) Tolerances are measured (hence the micrometer measurements.)
> Standards for the rotor are usually resolved by visual inspection.
> Hence the need for a picture.
>
> If your rotors are rusty on either wear surface after having driven the
> vehicle to the end of the block and back. The Rotors are probably NOT
> the problem. The calipers and pads need to be checked out. The pads
> should be in contact with the rotor. The caliper should move back and
> forth. The piston should respond to the brake pedal.
>
> On the other paw, if you have rust cracks WITHIN the rotor (as opposed
> to just on the surface), that could be a sign of a faulty rotor. Again,
> a picture would resolve that issue very easily.
>
>
> On Aug 16, 2004, at 3:27 PM, Eric Zeno wrote:
>
>> The only way to tell if the manufacture cut corners
>> in the alloy in the materials is to do a chemical analysis
>> of the material. Obviously I'm not going to do this.
>
>
>
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