guys i have replaced my wilwood rear rotors and pads due to some "major" cracks on rotor surface. it was making horrible vibration and noise when i hit the brake. anyways, after replacing rotors and pads, i have made brake in session as it is described, howvever, those f**ing rotors cracked just like the old ones in 300 miles!!!! what the hell is wrong with it? there is no problem up fronts? can it be a defect or anything else?? i ve sent an email to wilwood as well hope they will reply me. pls help!!!

 

Can you post pics? Are they drilled or slotted or just plain?

 

Could be a problem with the hardening process be it heat treatment or cryo. Drilled could be the culprit especially if the holes have not been chamfered.

 

i hv replaced the old one coz of a small crack on it, thats the previous one,




and this is the one driven about 300 miles!

 

I'm glad you took a picture of those rotors so others can see them, because I've seen those types of failures before in high-temperature as well as lower temperature applications. If you have to have cross-drills, you should enquire about obtaining a rotor at least without the holes being directly perpendicular to each other, especially with the inner hole partially overlapping the outer hat area and the outer hole being so close to the outer rotor edge.

Try to get replacement rotors without any cross-drills, slots, dimples, j-hooks, ellipses, or any other friction surface patterns, even if they're "casted-in" and/or chamfered. A plain rotor used instead would be optimal to see if this problem will repeat itself.

 

yeah i ll definately get a set of plain rotors but am hoping wilwood to replace them.

 

nobody has asked if you heat treated/heat cycled the rotors after install...

 

From the first post:

Just thought I should clarify. No flame intended.

 

none taken.... just missed it/wanted to make sure nothing was overlooked...

have you been braking hard such that the rotors could be over heating?

If they were heat cycled correctly and have not been overheated, I'm inclined to say bad material/casting.

I had a set of LG Coilovers (LG uses Bilstein ASN series shocks) that BOTH front shocks piston rods snapped. With both, the fracture point looked like it had been dipped it liquid nitrogen and then shocked (in short, material failure). This issue only occurred with the fronts (not the rears). The shocks were eventually traces back to the same batch which had many others failed. Swapped out for a new "batch" and never had an issue after that. My point, even the "best" designed products can have issues show up.

 

are these with the stock camaro calipers?? if so it is due to the sliding pins sticking! if u do not lube them the brake caliper can get stuck!

 

no they are not stock calipers. wilwood sl6 r up front and 2 piston on rears.

 

HELLO Taskin,

As per our email:

Email Dated 7-9-2008:

I am coding Justin Derose in this email so he can determine if Wilwood will cover your rotors under warranty.
Sorry to hear they went bad. In the future let me have a set of custom rotors made for you from another company we do it all the time.

I have attach a SAMPLE of an ordering form we use when we order the rotors. I always order the rotors balanced and gas vented.

It would also be a good idea not to order them drilled but plain or gas vented. I can also have the rotor made as a 2 piece instead of the one piece rotor you ordered. Rear part number 160-6976 and 160-6977 is shown in Wilwoods part number 140-7148 a Camaro Rear kit we do not sell this kit for the reason of your problem. Our kit would be B2C-2481782 this is a 2 pc kit with ½ stud. We can no longer get the 12mm hats so we use a ½ lug hat and send you ½ studs.

http://www.hotrodsusa.com/store/dpsrear_pbrake.html

To solve your future problems I would recommend you:
1. use a 2pc hat sytem our hat would be #170-6239 with 2.39” offset.
2. use a gas vent rotor or a plain rotor; and/or increase to a 1.00” wide rotor instead of the .810 rotor size. If you do this we will have to send you the correct spacers and bolts to make your calipers fit the 1.00” wide rotors.
3. use a different pad than the BP pads you used. The BP pads were not intended for racing. Switch the a H compound pad for racing.

Here is a link for you to read.

http://www.hotrodheaven.com/tech/brakes/

Brake Cover Sheet read the brake article and FAQs

In following the link to the Brake article please go to the rotor section for a detail explanation of what I am talking about 1 pc vs 2 pc rotors. As stated above we DO NOT sell the 1 piece rotor kits currently being offered by Wilwood part number 140-7139 to 7148. We have a special kit made up for us that uses a 2 pc rear rotor so it is not likely to crack or warp vs the 1 pc.

If you follow the link to the rear brake kit it shows you this.

It would also be a good idea to read the whole article to get some value out of it.

Any way I have no control on the Wilwood warranty policies, nor is any type of Racing Equipment have warranties, but we will try.

If Wilwood compensates you for the rotor it would be good idea NOT to replace them with the same and go to a 2 pc system like your fronts.
Gas vented or non-drill this time.

Dean Oshiro

 

Thats from Wilwood,


Taskin,

Thank you for the information. I needed to review the photos with other Team leaders in our department and look into the last time Hot Rods USA has purchased these items. The information sent is helpful.

Looking at your first set of rotors and the finish of the zinc wash on it, it looks to be ok with us. Brake pads and rotors are expendable items and if bedded correctly as stated, we can never give a time frame for what longevity the parts will sustain. Because the newer set of rotors are in better condition and I can look for more tell tale signs we will commonly look for; I am going to ask that you make sure we do not have any kind of dragging of the caliper during a non braking cycle. Meaning, let's make sure the brakes are not engaging when not in use. For only 300 miles of use, it looks like the parts have been used for a track day or very spirited driving because of the pad build up on the drilled and slotted areas. If the caliper is dragging, we will be generating excessive heat into the system promoting expansion and contraction of the rotor; ending up with possible cracked rotors.

With that said, what is the car being used for? I did not see that answered below. This question is important for many reasons. If the car is a daily driver that you may drive spirited here and there, this brake system and the choice of SRP rotors and street performance pads would be our recommendation. If the car is a daily driver, but taken to the track for 1/2 hour stints; the parts being used are not the recommended components. We would suggest a more aggressive pad that will take more temperature and have a higher cf than the street performance pad as well as a non drilled rotor, possible a plain faced rotor or a GT slotted only rotor. When we drill rotors, we are taking mass away from them which is what takes the heat and dissipates it. When a rotor is drilled and goes threw heat cycles during heavy braking it will cause the rotor to crack because it's expanding and contracting. The cracks will become pronounced because there is less mass and the crack will run from one drilled area to another much quicker.

Looking at the locations of the rotor's cracks being across from each other is something hard to explain. I would ask to also make sure the rotor is sitting square and flush to the axle end. If the rotor is not flush and any force is applied to the center register or lug locations when the wheel is installed; that may be a cause. Although pictures help, it is hard sometimes to determine and give specific answers for questions brought to light without the parts in question in hand. Understanding that you are half way around the world, a request to get the parts to us for examination is logistically very hard and we understand that. But, that would be our next step in determining what may be the cause of the questions you have.

I have taken care of Hot Rods USA's account for Wilwood for some time and looked at the last time a kit with these rotors was purchased from Dean, along with the last time just rotors were purchased alone. The last purchase made was over 2 years ago and that was for a kit. Rotors have never been purchased. This is being brought up because all of our components have a date code associated to them. Each part will have two letters that will give us the year and month the part was either manufactured or assembled. On these rotors, this is located on the back side of the rotor; the face that meets to the axle. I can find the batch that these were run in and see if there are any notes during manufacturing to see if any questions can be answer that way.

To conclude, let me know these topics to help answer more questions without parts in hand.

Car used for and driven how.

Calipers dragging causing excessive heat to be generated?

Date code for further investigation internally.

Kind regards,