Fordnatics List Archive

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Mail From: (email redacted) (Matt Silveira x257)

Chris:

The dealer probably replaced the pads with a type of semi-metallic or
metallic friction media. I had these on two different cars: H*onda and
Ch&vy and they made a racket all the time. I grew used to the noise
but.. . I know what you mean. You could try taking the car back to the
dealer or switching the pads to a different brand. I know REPCO makes
a nice pad and they STOP the car they're on. The hat warpage is
something I think we all must suffer (I surely didn't have to deal with
this with earlier model cars from the '60's and '70's with discs). I
suspect that they are using thinner rotors and sub-grade pad material
for lower $$. You could (as some manufacturers suggest i.e. M@zda)
heat treat the surfaces, but I can tell you from experience that this
isn't cheap. Something else to consider are cross drilled rotors.
They may increase stopping distance but should eliminate noise, heat
warpage, etc.

Good luck!!




Matt Silveira
System Engineer
OSI
(email redacted)
"Opinions expressed are not necessarily those of my employer."

Thought for the week:

Confidence is the feeling you have before you
understand the situation.

This read-only message was archived from a public mail list.
Mail From: (email redacted) (Matt Silveira x257)

Bob:

I would recommend that you take a pair of nice, new rotors, have them
checked for "true" a local machine shop and then follow these steps.
(First check Saleen, etc. to see if they may have these.)

1. Make a template and then cross-drill the rotors using it and some
machinist blue dycum. You should do this on a rotoary table mill to
make sure they are drilled true. Now chamfer each hole. There is an HP
book available at Pep-Boys (no really, its GOOD) called the Brake
handbook or something. IT IS A WEATH of Info!

2. Check for warpage again (from drilling stress).

3. Heat treat the rotor.

4. Buy REPCO metal master pads. They work great, don't "dust" and can
stop a locomotive. (And if you don't like them I still believe they are
guaranteed for satisfaction.)

Good Luck.



Matt Silveira
System Engineer
OSI
(email redacted)
"Opinions expressed are not necessarily those of my employer."

Thought for the week:

Confidence is the feeling you have before you
understand the situation.

This read-only message was archived from a public mail list.
Mail From: (email redacted) (Scott Griffith, Sun Microsystems Lumpyware)

On Jun 21, Matt Silveira wrote:

> 1. Make a template and then cross-drill the rotors using it and some
> machinist blue dycum. You should do this on a rotoary table mill to
> make sure they are drilled true. Now chamfer each hole.

I'd have to disagree. Drilling Fox rotors (unless it is done for a
specific reason, such as working around the green-fade characteristics
of a certain pad material that you need to use for endurance racing or
whatnot) is a big waste of time. There's no question that it can help
increase stopping power under certain conditions, but there's also no
question about the fact that it will reduce rotor life pretty
dramatically, especially with the OEM castings. I can't advocate doing
this type of expensive and time-consuming work on a street car. Hell,
I can't even advocate it on my *track* car!

There's also the problem that it will significantly _increase_ the
noise produced by the braking system, and not decrease it. I think
you're advocating solving the wrong problem.

> 2. Check for warpage again (from drilling stress).

More like from drilling stress relief.

> 3. Heat treat the rotor.

To what specs? The right thing to do for a race rotor is to complete
all machining operations except for the final surfacing cut, do a
stress relief bake (slow ramp from 400 to 1200degF over 4 hours, hold at
1200degF for 1 hour per inch of section thickness, slow cool to room
temp over 4+ hours), then do the final surface prep. This is all well
and good, but it doesn't really apply to street rotors (unless the guy
has money to burn!).

And it won't make the brakes any quieter. It'll just make them more
resistant to warpage, which isn't the problem here.

> 4. Buy REPCO metal master pads. They work great, don't "dust" and can
> stop a locomotive. (And if you don't like them I still believe they are
> guaranteed for satisfaction.)

And, last time I looked, were not available for the Fox application.

Seriously, the problem is basically that the pads are vibrating
against the caliper and piston, under light loads. There are several
brake squeal stopper materials that work pretty well for all but the
most intractable pad materials. I have used the CRC and Duro products
at various times with good success. These are basically a glue that
fills the voids between the pad's backing plate and the caliper or
piston. This provides some damping that kills the high-frequency
chatter that actually causes the squeal, and is easy to install in the
privacy of your own driveway.

There's a finite chance that the pads themselves are not bedded into
the rotors well, or that they are a material that simply "likes to
squeal". There are several race pad materials that behave this way,
but I highly doubt that that's the problem here. If the squeal can't
be stopped through the use of the glue goops, then I could suggest a
couple of (moderately dramatic) pad bedding procedures that would help
kick off any glaze and might help with the noise. In the worst case, a
change of pad (to Performance Friction's street carbon metallic pads,
or the Onadime Carbomet Plus pads) will fix it. But I'd be willing to
bet that the squeal stopper glue will do the trick. The OEM pads are
pretty well behaved.

Don't attack the problem with a sledgehammer when a leetle-bitty
ball-peen will do...

-skod

- --
Scott Griffith, Sun Microsystems Lumpyware
expatriate SCCA New England Region Flagging/Communications worker
(and driver, of anything that turns both right and left,
and can pass tech...) Return Path : (email redacted)