[s-cars] Cracked Big Brake Brackets - ECS Stage 2

Mon Oct 23 19:35:00 EDT 2006

I don't believe that it's a problem in the materials per se, but the
manufacturing.  More specifically, the process in which the caliper brackets
are threaded that poses a heat cycle issue.

ECS has admitted to the problem and will send replacement brackets free of
charge.  Just one more thing to check when you're changing pads.

On 10/23/06, Mark Strangways <StrangConst at rogers.com> wrote:
>
> I suppose the same hold true for the Aluminum calipers, they are made of
> the
> same materials you dislike, and also suffer from the same (if not worse)
> stresses that are imposed on the brackets.
>
> So, all you guys out there with 993 calipers, please pull them off...
> I will provide a shipping address for you to send them to :-)
>
> Ohh wait aluminum wheels too, send those as well.
>
> Eric, I have read your argument on the BIRA list, while I surely agree
> Aluminum is not as strong as steel, I think it's adequate for the job at
> hand. I will keep my brackets and hats, calipers and wheels.
>
> YMMV, and this is just my 2 cents worth of course.
>
> Mark
> ----- Original Message -----
> From: "Eric Phillips" <gcmschemist at gmail.com>
> To: <s-car-list at audifans.com>
> Sent: Monday, October 23, 2006 1:12 PM
> Subject: Re: [s-cars] Cracked Big Brake Brackets - ECS Stage 2
>
>
> > Guys:
> >
> > I think that it's a design flaw - due to *materials choice*.
> >
> > Aluminum is the material from which this - and other - BBK brackets
> > are made.  Aluminum has no fatigue limit, which is engineer-speak for
> > being able to take ZERO stress without weakening the part made from
> > aluminum.  Different alloys have different fatigue strength, which
> > tells you how many cycles it takes to break that material.
> >
> >
> http://www.sv.vt.edu/classes/MSE2094_NoteBook/97ClassProj/anal/kelly/fatigue.html
> >
> > Steel has a fatigue limit, which means it can take an infinite number
> > of stress cycles below the that limit, and will only begin to fatigue
> > when the stresses happen above the limit.
> >
> > This is the simplified version - but it is the basis for which I have
> > decided to always recommend against BBKs with aluminum brackets.  Of
> > whatever alloy.
> >
> > Brake brackets get stress in two directions every brake cycle.  In
> > addition, one has to be careful about the torque put on fasteners
> > around aluminum.  Too much can create a stress riser that will lead to
> > cracking.  So, if your torque wrench isn't calibrated properly, you
> > could initiate a crack on the first install of a new BBK.
> >
> > On any other automotive system, I don't think it'd be that big a deal.
> > But brakes are *the* primary mechanical safety system.
> >
> > The next problem is corrosion.  The environment in the wheel well is
> > pretty harsh.  Aluminum is more reactive than steel, by it's nature.
> > Surface treatments and alloying mitigate this, but don't eliminate it.
> > Add to that galvanic corrosion from marriage to steel fasteners, and
> > all of a sudden you have a potential problem.  And that's before any
> > addition of road salt.
> >
> > The reason to use aluminum in this application is price.  Cheaper to
> > make stuff out of aluminum than steel.  Who wants to pay $600 for a
> > pair fo steel brackets for a BBK?  That may be an exaggeration, but
> > not by a large amount.
> >
> > Maybe somebody could run an ECS, MoVit, StopTech, BIRA or other such
> > aluminum bracket on their BBK forever without any worries - especially
> > on a street-only daily commuter.  Maybe it would take over a million
> > cycles to even approach the fatigue strength of the brackets.  I don't
> > know.  But that's not something I'd like to find out by accident, pun
> > intended.
> >
> > So, now to the opinion part.
> >
> > I wouldn't run aluminum brake brackets on my car.  Any of them.  And
> > my car will never see the track.  Even the spirited driving I do is
> > pretty mild.  During my research on BBKs, I came to the conclusion
> > that the 993TT caliper, RS2 (steel) bracket and A8L D2 rotor was the
> > way to go.  From a price and hassle standpoint, the ECS kit is the
> > best choice.  But I just couldn't bring myself to put an aluminum part
> > there.
> >
> > With the RS2 bracket and the A8L rotors, some material has to be
> > machined away from the bracket where it contacts the strut - about
> > 1mm.  And the stock bolts (35mm) have to be cut down to 25mm, but that
> > costs about $20 and takes all of two hours for any machine shop that
> > can do it.
> >
> > Rotors are available and relatively inexpensive, and you can get them
> > plated and slotted from Apikol, if that's your thing.
> >
> > Also, you can run Porsche 993TT rotors on custom hats.  Then you
> > wouldn't have to machine the brackets at all.  And the rotors are
> > wider, so you get more life out of the pads, and the rotors are MUCH
> > lighter than the big A8 boat anchors.  Custom hats are in the
> > neighborhood of $450 for the pair.
> >
> > So, my opinion, FWIW, is to go 993TT calipers, RS2 brackets, and some
> > flavor of rotors that suits your fancy.
> >
> > You could change over for as little as $350 - $200 for the brackets,
> > and $150 for the pair of rotors.  I would consider that cheap
> > insurance, but again, that JMHO.
> >
> > YMMV, does not include batteries, may contain nuts, etc, etc.
> >
> > Eric
> >
> >> Date: Mon, 23 Oct 2006 08:30:21 -0700
> >> From: "Alvin Labonite" <alabonite at gmail.com>
> >> Subject: Re: [s-cars] Cracked Big Brake Brackets - ECS Stage 2
> >>
> >> I heard that chatter too and was very concernd. during that time, I had
> a
> >> shop installed my RS2 turbo and EM and they brought up the crack
> brackets
> >> too upon seeing them on the net. Mine turned out ok and they suspected
> >> that
> >> over-torquing may have played a factor. but who know's it could also be
> >> poor
> >> design.
> >> On 10/23/06, manuelsanchez at starpower.net <manuelsanchez at starpower.net>
> >> wrote:
> >> >
> >> > S-heads,
> >> >
> >> > I was having my tech inspection for upcoming VIR school and found
> that
> >> > both of my ECS Stage 2 caliper mounting brackets are cracked. Based
> on
> >> > some
> >> > recent internet posts on the subject, I made sure the tech checked
> >> > carefully.
> >> >
> >> > I spoke with Gary at ECS, he was very nice and did some checking with
> >> > the
> >> > returns department. He told me he thougght this was an isolated
> >> > incident. I
> >> > mentioned that I was clued into this potential problem from chatter
> on
> >> > the
> >> > net, but he said he had never run across the issue and he handles 50%
> >> > of the
> >> > calls.
> >> >
> >> > I would be interested to know how many others have had this problem
> and
> >> > what you did about it (contacted ECS?).
> >> >
> >> > I asked if the design had changed at all, and he said no. I suppose
> it
> >> > could be an isolated manufacturing defect, but I wonder if it is a
> >> > design
> >> > issue. Obviiously I would prefer that this not happen again, and a
> >> > design
> >> > revision would probably make me sleep better.
> >> >
> >> > So check you caliper mounting brackets.
> >> >
> >> > Again, Gary was very nice and helpful, and ECS will warranty the
> >> > brackets.
> >> > I need to buy new brackets, returned the cracked ones, and then they
> >> > will
> >> > refund the cost of the replacement brackets.
> >> >
> >> > I'm wondering though what my other options would be for a 993TT Big
> Red
> >> > brake kit. Any thoughts?
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