NAC: Stainless brake lines on a street car?

Mark R speedracer.mark at
Sat Jun 24 18:34:24 EDT 2006

That's almost happened to me with stock (plain finish) brakes.  If I'd not
noticed the crack, the neaxt heat cycle would've exploded them, and probably
in trail braking (max heat), and probably locking up a wheel.  The resulting
spin just couldn't have been good!  Luckily, I happened to look at the
brakes when eating lunch.  It became a good show-and-tell for students.  Oh,
the crack was through both sides of the rotor, about 2" long, propogating
from the outside to the hub of the rotor.
When lines fail like Scott's did... that was a crimping issue, not an
abrasion issue.

I disagree with your assertion on the stainless lines, especially after a
year, and especially with initial bite and pedal feel.  Also, on some cars,
the heat reflectiveness is necessary.  But your point about being able to
inspect the line is valid.  Hence the recommendation to change them with
some regularity, something most people ignore.  Brake lines just aren't that
expensive.  Change them!

I've seen a LOT of stock rotors fail, including Porsche's cast-in holes.
When my Z06 was new, I almost had a (catastrophic) failure personally (see
above).  The only time I've seen stock lines FAIL is when old, and/or
subjected to a lot of heat, but I've definately seen them fail.

It's worth noting that there's no such thing as "DOT approval."  Anyone can
put that on brake lines, as long as they are manufactured to DOT
guidelines.  But there's no (legally speaking) independant testing legally
required.  Some brake companies definately do a better crimping job than
others.  Personally, when I look at a new brake line manufacturer, all
I study is the crimps.  Everything else is purchased (rolls of line,
fittings, crimp collars, etc.).

Brett, thanks for the comments on the Stoptechs.  IDK if you've ever been
for a ride in my S4 on the track, but I have Stoptechs installed there as
well.  One of my selling points for the Stoptechs is that pads are Porsche
911 (993 Front) size, and rotors are standard Brembo sizes (including hat
bolting).  So EVERYONE makes friction (inexpensively) for the Stoptechs, and
you're don't even have to buy replacement rotors from them.  Oh, and the
dust seals- same thing.  Standard sizes.  Of course, Stoptech has some cool
patents, but I'm not trying to do a sales pitch... just clarifying what
Brett said.

Mark Rosenkrantz

> Oh, and a year or two ago, a student lost a wheel when one of his
> drilled rotors cracked and exploded.  Ripped the caliper off the
> strut (cutting the brake line, so no brakes), shattered the wheel,
> and shredded the tire.  The student said it sounded like someone set
> off a grenade in his wheel well.  Looked like it, too.  Funny how
> I've never seen stock brake lines or stock rotors fail, huh?
> Fascinating.
> There is NO way to inspect an SS line, unlike regular stock lines.
> Improvement in pedal feel compared to NEW stock lines is minimal and
> pointless.  SS lines are for the track/racing, stock is for the street.

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