Wilwood Failure

[D1cker]

Originally Posted by Hanakuso

But isn't this specific Wilwood mounting basically the same as the "Sprint" kit?

Yeah AFAIK the sprint kit rotors are mounted the same as this failed wilwood kit. The Endurance kit however does use floating rotors.

[Captain Snooze]

Originally Posted by jamal

Most other two piece rotors use a drive pin with float which allows the rotor to expand independently of the hat as well as reduce brake piston knockback. The wilwood hats are just straight bolted on there.

"That said, we have many hundreds of our CP3862 discs on Late Model racecars using the fixed hat, and we never have any reported problems of stress-related cracking due to the fixed hat."
From http://www.essexpartsblog.com/news/f...ng-brake-discs

[SubieNate]

The Sprint kit does have a through fastener with a bolt on the other side vs a tapped hole in the aluminum. I'm not sure if that makes a difference.

[AZFA20]

I am going to throw this out there but does anyone know if this vehicles wheel bearings were 100%? I tried to read the original thread but my work computers for whatever reason will not let me access that S2K forum. Excessive wheel bearing play would certainly transfer a significant amount of lateral force during braking in a corner to the friction disk (although braking should have been completed prior to this stage). This combined with a fixed caliper could have created issues over time at the mounting points. Lets face it, those rotors have seen some use so if excessive deflection had been happening it may have been for some time. If the deflection were bad enough I would guess even a floating friction disk would have failed eventually at the weakest links (The mounting points). You can only TQ metal so many times before it becomes weak.

[CSG David]

Originally Posted by AZFA20

I am going to throw this out there but does anyone know if this vehicles wheel bearings were 100%? I tried to read the original thread but my work computers for whatever reason will not let me access that S2K forum. Excessive wheel bearing play would certainly transfer a significant amount of lateral force during braking in a corner to the friction disk (although braking should have been completed prior to this stage). This combined with a fixed caliper could have created issues over time at the mounting points. Lets face it, those rotors have seen some use so if excessive deflection had been happening it may have been for some time. If the deflection were bad enough I would guess even a floating friction disk would have failed eventually at the weakest links (The mounting points). You can only TQ metal so many times before it becomes weak.

The car is built by a team/crew that regularly builds/maintains their cars for 25 hour Thunderhill enduro races and podiums for good measure. They have the knowledge and expertise to keep cars quite reliable so I doubt this is something they overlooked. This particular car wasn't exactly running scorching times that day either when it happened. Shocking image though right?

[DAMotorsports]

Originally Posted by CSG Mike

The car in question typically has a full crew regularly working on it...

Mike it appears you may have the best knowledge about this vehicle. So ill ask a few questions to maybe help get a better understanding. I run this same type of rotors on my race car and have done so for the past 5 years without any problems. so I am interested in this topic also.

Do you know how long that rotor was on the car?
When was it last inspected?

I'm assuming everything was safety wired so the bolts wouldn't back out. I have seen bolts back out and cause cracks in the mount points not saying that is what happened here. Being that I run endurance races I have gotten I to the habit of checking the brakes regularly and this includes removing the rotor from the top hat and I have not had any problem to date other then normal wear of the rotor.

[Huehuecoyotl]

Going Endurance myself...
this is SCARY to look at

[Supermassive]

Hey look one dude had a rotor failure on his race car! That must mean all the other people using that brand are gonna have the same issue, better run for the hills!

This is why the internet is idiotic.

Seriously, that rotor looks like it had been run hard for quite a while, you can see the wear had actually left a nice little lip around the hub. Not to mention that the slot wear indicators are flush with the rotor surface. The fact that these are used on a "professionaly" maintained racecar leads me to question just how diligent those inspections were, rotors are a CONSUMABLE resource, just like pads, brake fluid, etc.

This failure sucks, but like someone else said, metal can take only so much stress before it fatigues and eventually breaks. The other side of the coin that has yet to be shown is the condition of the other rotors, if they are all worn the same way, but have no stress fractures, then it could be surmised that this was a defective part. Shit happens, I've seen brembo rotors self destruct on bikes before, a name brand doesn't ensure that you will have no issues.

Here's some more things to consider, the rotor in that pic is an 8 bolt pattern...probably this exact rotor:


While Wilwood's newer kits, specifically on our car are a 12 bolt pattern like this :



Pretty beefy and a failure like what happened to the S2K would require a tremendous failure or impact to occur with this design.

Personally, I think it was negligence on the team maintaining this car, that led to this. I don't race, and I would never drive my car on the street with rotors worn like that. So yeah I may be partial to Wilwood because I have them on my car, but it's not out of fanboyism that I do so. I was going to run the AP kit but I realized that if I was gonna spend that kind of money on brakes I would just get Brembos. Sure AP is nice but I've had Brembos on most of my sport bikes and love their product. The Wilwoods price can't be beat, the kits are way lighter than AP's endurance kit (same rotor diameter as well as 6 pistons instead of 4) and cost $1000 bucks less.

So enough ranting, I'll let the internet go back to making wild assumptions about the quality of parts a manufacturer makes based on a picture of broken rotor.

[SubieNate]

No one here is trying to fearmonger or bash Wilwood. We are simply asking, was this a failure caused by negligence or is there a flaw in the way the Wilwood disk/hat connection is designed, or was this particular rotor just defective?

There are some parts where one catastrophic failure is reason for concern. This is one of them. Brakes are extremely important. There's no reason to get butthurt because people on a forum are discussing a failure that happens to relate to the system you have on your car. Jumping to the conclusion that it was entirely the race team's fault is no better than saying all Wilwood products are junk because of this. Both assign fault without knowing all the facts.

Cheers
Nathan

[Calum]

Originally Posted by jamal

I have never liked the way the wilwood rotors go together. IMO the reason this happened is because there is zero float and no ability for the rotor/hat interface to compensate for thermal expansion or a slight misalignment.

Most other two piece rotors use a drive pin with float which allows the rotor to expand independently of the hat as well as reduce brake piston knockback. The wilwood hats are just straight bolted on there.

Here's a nice post by essex that explains the difference with more detail
http://www.essexpartsblog.com/news/f...ng-brake-discs

And Stoptech has some pictures of their mounting system here:
http://www.stoptech.com/products/rot...ch-aero-rotors
and more here: http://www.zeckhausen.com/StopTech/R...eplacement.htm

For anyone reading these the bevel washer is a typo, that's a belleville washer. They are used to act as a springs to allow expansion of components without putting undo stress on fasteners, or requiring unrealistic fasteners that could expand with the other components.

[Calum]

Originally Posted by Supermassive

Personally, I think it was negligence on the team maintaining this car, that led to this. I don't race, and I would never drive my car on the street with rotors worn like that. So yeah I may be partial to Wilwood because I have them on my car, but it's not out of fanboyism that I do so. I was going to run the AP kit but I realized that if I was gonna spend that kind of money on brakes I would just get Brembos. Sure AP is nice but I've had Brembos on most of my sport bikes and love their product. The Wilwoods price can't be beat, the kits are way lighter than AP's endurance kit (same rotor diameter as well as 6 pistons instead of 4) and cost $1000 bucks less.

With all do respect to the crew that put that car together, I've got to agree with Mr. Massive. Looking at the pics it looks like those rotors have had a VERY hard life. If they choose to run a kit without floating mounting points wouldn't they have to put a life span on the rotors or preform some form of NDT on them between events? A simple LPI isn't THAT expensive and should have indicated this was in the near future if it had been done.

Again, from what I can see in that picture, I wouldn't contribute that to Wilwood.

[mrk1]

Originally Posted by CSG Mike

I was there first hand and witnessed the off. The owner was driving. What do you want to know?

What happened? any contact with anything? or normal braking scenario?

Now knowing that you were there and haven't mentioned any contact thats probably off the table. However it still makes my point. More information always helps.

[bpracer]

Originally Posted by SubieNate

Found this on an S2ki.com. Figured it'd be interesting to talk about considering the similarities between our two cars. The car was running RS3's when it went. This was an on track failure.

Has Wilwood had any recent design improvements to rectify this type of failure? The thread wasn't that old, not sure when the pic was taken.

Cheers
Nathan

Why would you run a stock dust shield on a racecar??? I am also surprised the cast iron rotor failed rather than the hat. Something is very suspicious here. It doesn't looked very well maintained.

BTW, newer S2000 Willwood kits have 12 bolts.

Edit - I've used 8 bolt Willwood hats on my racecar (production calipers, Coleman custom rotors), with ARP hat bolts that were safety wired. I do remember the hats had runout as did some other brand hats I've used and had to be machined true.

Yes APs throughbolt w/ jet nuts is nice but you can't always package things that way. And if you think Brembo is the ultimate, they had a rash of rotor failures in some BBK kits for mid 2000's Mustangs.

[jamal]

Originally Posted by bpracer

Why would you run a stock dust shield on a racecar???

Why wouldn't you?

That one is modified for the brake cooling duct plus it protects the ball joints and tie rods.

Just because the rotors weren't brand new doesn't mean you should expect a catastrophic failure like that. I know a little about that car and it's pretty well maintained and put together. Plus it's n/a and on street tires so there's not even that much stress on the brakes.