Clicking from Front Rotors
 

A while back I had an annoying clicking noise coming from the front wheels, it was only after spirited driving so you could assume it was caused by heat. Diagnosed by 2 reputable works shops as faulty wheel bearings, you can spend anywhere from $500 - $1000. Second hand, low km parts or all new hubs and bearings are the options. After this mandatory spend I was not impressed that the noise was still there. Closer inspection proved it was being caused by my new 2 piece rotors.

Several others on this forum experienced the same fault and this was taken up by the Manufacturer with many emails and calls. One set was sent back for investigation. To the best of my knowledge the fault has never been addressed leaving me wondering how many other people around Aus. and the world have been pissed off by this issue. Remember it costs $1000 first for hubs and bearings before most people realise its the rotors. One guy over east replaced 2 sets of bearings and hubs and both CV's before he found it was the rotors !!!!!!!

I found the Rotors being anodised move against the hub or rim when hot. Called "metal pickup" by Engineers it’s due to the difficulties of clamping dissimilar metals whilst applying heat. This click click noise was very loud and what I would call "not acceptable behaviour" (said with Super Nanny accent) from any rotor. I used a torque wrench to manufacturers specs during testing.

I then removed the anodising from parts of the rotor Top Hat that contacted the rim and hub. Aesthetically this is not an issue and things look as bling as before, it's just not something I enjoy doing to $800+ rotors. I used a coarse then a fine wet and dry sand paper with a sanding block and 5 hours of elbow grease. The sanding block is necessary to keep things square, take your time as it would be very easy to unbalance the rotors. Not sure if it’s the hub or rotor side that caused it but who cares, it’s gone now. I have since added some Coppra Coat high temp grease to the same mating surfaces to reduce the wear rate. A year later and they are still behaving themselves.
Disclaimer: Its your problem if you stuff it don't blame me.

Photo's taken after a month of use before using Coppra Coat Grease, note the wear marks.
[IMG]http://i31.photobucket.com/albums/c379/my99maddog/Other/102-0241_IMG.jpg[/IMG] [IMG]http://i31.photobucket.com/albums/c379/my99maddog/Other/102-0233_IMG.jpg[/IMG]
[IMG]http://i31.photobucket.com/albums/c379/my99maddog/Other/102-0234_IMG.jpg[/IMG] [IMG]http://i31.photobucket.com/albums/c379/my99maddog/Other/102-0237_IMG.jpg[/IMG]

Had clicking on my MY98. Turned out that I had worn down where the pads touch the rotors but left about a 1 mm wide lip round part of the outer edge. Every time the pad went past it would click.

I couldn't see it till someone pointed it out. C&J I think they are in Adelaide. (Day before driving to Perth on last run in the hills did it) Very small but enough to make a noise.

Easy solution, MY99 4 piston calipers and bigger rotors. :D :D :D

good post morgan,
i should have a look into this as i think im suffering similar issues with my 2 piece rotors as well,
seems only to happen after getting them hot, regardless of pad compound (i originally suspected pad-knock).
cheers.

How hard would it be for DBA to make a non-anodised version?

[QUOTE=BLUES]How hard would it be for DBA to make a non-anodised version?[/QUOTE]
Yeah good call! They could even mask off just the contact areas as its not even visible when bolted up.
thanks tuna
After I had worked this out myself I spoke with a mechanic that prepared GTP WRX's and he said: "We remove the anodising for just that reason"....aarrrgghhhhh

Oven cleaner is a great way of de-anodizing something yourself. Just be careful you dont leave it on too long or it'll start eating the aluminium!

Best thing to do is spray it on, leave it on for a little bit (say 10-20 seconds) and start rubbing with a cloth until the anodizing rubs off....then once that is done, rinse the rotors straight away to get the oven cleaner off.

This way, you wont risk leaving high spots with sanding.

Also, the oven cleaner must be a caustic one i.e. toxic, hazardous....caustic free oven cleaners will not strip the anodizing.

Excellent post Morgan...thankyou
Here is some more info on the matter from my personal experiences. I too had the same problem on the MY02 STi (that car had Australia's very first DBA 5000's made for a Brembo equipped Subaru...they were prototypes given to me by DBA for testing and they let me keep them!)....they were on the car for almost 4 years and it was only in the last year or less that the clicking started...at first just noticable, but it got worse.
I used to get it only while turning and with the brake pedal depressed (ie pads against rotor) it went away.
I tried chamferring the pads (DS 2500's) and it went away for a while then gradually came back. MMS were very skeptical about wheel bearings being the issue but I replaced them anyway since one was a little dodgy...no clicking for a week then back again! I put the standard rotors on when I traded the car and of course the problem disappeared, though I still experienced some pad knock off. So in the end I put it down to pad knock off making the edge of the pads catch the slots in the rotors. I put the pad knock off down to slightly cooked piston seals on the Brembos due to 4 years of motorsport.
I also put the problem to DBA back at the beginning of 2005 and they couldn't offer any explanations, so I'm happy you kept at them to work it out, though I still suspect there may also be some other additional minor factors at work. I have the DBA 5000 rotors from the '02 (albeit another near new pair) on the MY06 STi (but with new 114 PCD hats) and so far no problems at all...it will be interesting to see how they go over time. And the brakes have been fairly hot on the '06 too (at Collie)...in fact hot enough to turn the red "Brembo" writing on the front calipers black!

Agreed. Well done. Will be cleaning mine before I install them. Will try tonight. Will take some photos. I like Joe's idea of trying with the oven cleaner first.

Let you know how I get on.

Cheers

Brendon
Try removing the anodising in stages, i.e. just do the inside of the rotor first and see if that sorts it. Test it for a few events and let us know the results? I lost the opportunity to confrm what side caused it when I did both of mine simultaneously :o

Worth adding something Steve mentioned: It clickety clacked ONLY when turning and in my case it also had to be hot.

Did it do it from new or only once they had been used for a while?

Just out of interest has anyone replaced just the rotors and kept the original top hats? Obviously this will not solve the problem but I am just thinking down the track.

Thanks