Wilwood Brake Rotors- Check Em!

[MINX]

Hope to get the new friction rings end of this week - will post disassembled pics then

Fedex Status

5/21/2013 - Tuesday
1:30 pm
In transit
HONOLULU, HI

[Charlie Brown]

You got proof it does?

Surely the 150-300 degree temps the brake componenets run at is good enough for water dissipation, since water seems to dissappear in a cloud of steam at around 100 degrees.

Just thought the slots were for out gassing.

On the track my DBA T3 rotors paint temperature indicators showed a temperature exceeded 630 degrees C , using Hawk Blue's that have a temperature rating of 100 - 800 degrees C.
I'm now using the CarboTech XP12 with a 121 - 1093 C range.

For reference:
Hawk HPS has a maximum temp of 399C.
Hawk HP Plus a maximum temp of 510C.

CarboTech 1521 a maximum temp of 426C.
CarboTech AX6 a maximum temp of 593C.
CarboTech XP8 a maximum temp of 732C.
CarboTech XP10 a maximum temp of 898C.

[project.r.racing]

Street dríven example, which I failed to mention in my post. But yes double for trackwork.

[MINX]

OK - new rotors, friction plates arrived today, ordered Monday night.
I have installed and done a quick bed in test run and all good.

Here are pics of the damaged rotors.
Bit scary.
All bolt hole tabs had cracks.

[greenMachine]

Did you assemble them?

Were they all tight when you took them apart? Did they have safety wire?
While this may be just hard work taking its toll, it might also be loose bolts. Or maybe one or two that were loose.

[MINX]

They did seem all tight with safety wire still in tact
Response from Emilio was also possible loose bolts and that it is not common for these to crack
He also recommended a higher torque spec than in the instructions
So looks like I will get some practice taking them off again an torquing them higher

[greenMachine]

He also recommended a higher torque spec than in the instructions

Care to share those specs?

[MINX]

15-18 foot lbs. They only crack there if the bolts come loose. We have run the 25 hrs and many 3 hr enduros on those without issue. We cracked tabs on one individual rotor early in develpment and it has loose bolts.
Emilio Cervantes
www.949Racing.com

The instructions that come with them state only 85 Inch Pounds ( 7 foot pounds)

[greenMachine]

15-18 foot lbs. They only crack there if the bolts come loose. We have run the 25 hrs and many 3 hr enduros on those without issue. We cracked tabs on one individual rotor early in develpment and it has loose bolts.
Emilio Cervantes
http://www.949Racing.com

The instructions that come with them state only 85 Inch Pounds ( 7 foot pounds)

Thanks.

Mine are about due for replacement, in fact I have the new ones sitting in the garage already, including new bolts.

As a matter of interest, how were the brakes before you found this - any vibrations, noises, etc?

[MINX]

They were fine on the road
BUT
I did have a weird 'cracking' noise which had just started, when at low speed came to a stop or started away
I had checked by Automotive plus the week before and they did not diagnose this
They thought it was just play in the pads
But On The track they started to grind, like when your pads are worn out under heavy braking

I now know the earlier noise were probably the cracked tabs rubbing
Scary

[project.r.racing]

wow wouldn't have thought 7lbs/ft would be enough.

[949Racing]

Sorry for reviving an old thread..

The cracking shown in the OP (original post) is due to insufficient torque on the mounting bolts. That is the only way the mounting tabs will crack like that.

[Hellmun]

I just had the exact same thing happen to me. 2 track days and the rotors tabs all cracked and the cracks reach halfway through the total rotor surface. I had no vibration or ill effects other than my brake pads also being down to the backing plate with huge amounts of deposits on the rotor. In total I'd say I've done <60 laps on the rotors/pads and I have TSE brake ducts. I assumed it was just me being above the temperature range they can handle rather than the torque set. On low boost I have about 190kw which I was using both days, though I did a cool-down run up the road after each session so never got the infra-red temp gun on the rotors to get an estimate of temp. I just followed the wilwood instructions on torque and used some high temperature loctite. Mine were also the super miata directional vane too, I'd try another set with the higher torque setting but I've already ordered a 298mm(11.75") kit as with the pads destroyed my pads must've been reaching/exceeding 1100C (XP12 limit).... Plus from the MT.net threads it appears most of the turbo guys get 2-4 trackdays max out of these 280mm rotors. They are thinner and lighter than the 270mm sport rotors they replaced.

[949Racing]

I think I know what's happening. We don't use the safety wire on our race cars, we use red loctite and torque to about 20 ft lbs, almost triple the 85 in/bs (9.6nm) torque spec in the Wilwood instructions. Over hundreds of hours of racing on a fleet of cars, we have never had one crack. We had one that was just hand snugged in our spares box. It found it's way onto a car for a 3hr enduro without being torqued and cracked through the tabs right away. We still won .

I'll start adding a note along with all of our directional rings ( we offer 4 variants) to torque to 20 ft/lbs, that's about 27nm. Max torque for the grade 8 5/16-18 fastener is 24.6 ft/lbs but we go just under that. There is no inherent design or casting flaw there. The only way they'll crack is if the load on the fastener is in shear instead of tension as it should be. So regardless of which kit you are using, I suggest running 70-85% of max fastener torque on hat bolts.

What I wonder is how Wilwood comes up with the spec on the fasteners for their low cost 160-5840 rotors.

[greenMachine]

Yet another thread resurrection! Updating as this thread is an important resource for we Wilwood users.

I am finally installing my new rotors. The bolts now have a leaflet which states 5/16 bolts torque 180 in-lb, which is I think 15 ft-lb. Still a bit off Emilio's recommendation of 20 though.

I am going with Emilio and making them 20.

Haven't pulled the old ones off yet, will look carefully for cracks when I do. I can't remember what we used, but it was more than the then recommended Wilwood number, so it will be interesting to see how they have stood up.



Just remembered (must be getting forgetful in my old age) - we replaced the hats/rotors a while back as we couldn't otherwise get rid of a bad vibration in the car under brakes - duh! I must chase down those and have a close look at the tabs. I think I know what I am going to find.