[s-cars] Woah! pics link

[Taka Mizutani]

I do recall something about the improvements that ECS made to their brackets
after the whole cracking thing came to light several months ago.

I do know that ECS will replace existing brackets at no cost to the
customer, other than shipping, IIRC.

After the whole ECS debacle, there was another debacle about BIRA and debate
whether or not BIRA's brackets may do the same thing, but I don't think any
cracking reports have occurred with the BIRA brackets.

I thought the ECS brackets placed the caliper in the same orientation as the
RS2 brackets. If that's not the case, then using RS2 brackets would
necessitate a custom hat or the use of A8L one-piece rotors. At least the
RS2 brackets are forged steel, so the chance of stress cracking is much
lower.

Taka


On 7/18/07, Paul Gailus <gailus at mindspring.com> wrote:
>
> While I'm not a metallurgist, I have a suspicion that this failure
> could've been caused by stress corrosion cracking and/or fatigue cracking
> along the grain of the aluminum alloy. Hot-rolled plate stock will tend
> to have some unrecrystallized grain structure in layers that can act as
> slip planes in a fracture.
> For example, see the discussion at:
> http://www.key-to-metals.com/Article114.htm
>
> Being in the "salt belt" probably didn't help either, Bill ;-)
>
> Some suggested alternatives in the design would be:
> 1. use an alloy more resistant to stress corrosion cracking, and include
> ferrous alloys in the selection process
> 2. counterbore for a steel nut so that the aluminum bracket doesn't have
> to be threaded and therefore be more susceptible to stress/corrosion.
> 3. the existing counterbores for bolts to the strut housing could
> have a larger radius applied with a ball mill to minimize stress
> raisers.
>
> Perhaps the redesigned brackets have some improvements in these or other
> areas.
>
> Paul
>