Rattle, Rattle, Rattle. Alcons?
 

I'm loving my CSL but if I put the window down when running at low speed on a bumpy surface it sounds like a bag of spanners! Not Good.

However. I've noticed that just the lightest touch on the brake pedal will stop the rattling. This makes me think that the noise is coming for the Alcons I'm running on the front. Could it be the pads rattling in the calipers or the disks rattling on the bells? Or all of the above. Has anybody who's running Alcons suffered the same issue and resolved it? Or is it something I have to live with?

A quick peak through the front wheel tells me that I do have anti rattle springs fitted in the caliper. Well the offside one at least, I never checked the near side.

I notice from this month's EVO David Yu may be suffering from the same issue.

Any advice would be greatly appreciated.

Cheers

Gregor

Don't you just love floating disks !!!!


QUOTE=GregorFuk;179864]I'm loving my CSL but if I put the window down when running at low speed on a bumpy surface it sounds like a bag of spanners! Not Good.

However. I've noticed that just the lightest touch on the brake pedal will stop the rattling. This makes me think that the noise is coming for the Alcons I'm running on the front. Could it be the pads rattling in the calipers or the disks rattling on the bells? Or all of the above. Has anybody who's running Alcons suffered the same issue and resolved it? Or is it something I have to live with?

A quick peak through the front wheel tells me that I do have anti rattle springs fitted in the caliper. Well the offside one at least, I never checked the near side.

I notice from this month's EVO David Yu may be suffering from the same issue.

Any advice would be greatly appreciated.

Cheers

Gregor[/quote]

Mine don't do that.

They clank a bit here and there on light application - eg pulling on to the drive or in car parks but otherwise no real noise from them.

They are the Alcon Extreme discs which I think are semi floating rather than fully floating.

Mine were bought second hand by the previous owner from a register member. I assume they came from shane@mbtech.

http://www.cslregister.com/forum/sho...ighlight=alcon

You might be missing some pad retains clips like on the APs

If they are floating then you would hear them with the windows up (but yes bag of spanners). Possibly just clips as shim says if its quieter than that

My APs do the same. I just drive faster/brake harder... :thumbs:

fuck me.....youve changed. Have you grown a beard as well.

Gregor,
They were brand new and done 3 track days prior to the sale. All the clips were there when fitted but whether John put it in anywhere after they were fitted I couldn't say.
They were indeed from Shane as he was the one who fitted them onto the car under his ownership.
Its just a trait of the big brakes I'm afraid.
I would be interested in buying them back if you wanted to go back to standard???

Easy fix if its got floating discs fit 4 nissan GTR disc springs sorted
they let the disc move when hot but hold them from ratteling :thumbs:

HOW IT WORKS

During braking, torque is transmitted from the disc to the bell through a fastener called a bobbin. This type of mounting system is designed to allow a specific amount of float in both radial and axial directions. This allows the disc to expand and contract under high temperature which reduces stress and increases longevity of the related components.

Brembo's unique anti-rattle disc hardware utilizes a spring fastener in order to slightly preload the assembly which eliminates the noise generally associated with floating discs.
http://www.racetechnologies.com/imag..._bobbin-id.jpg


http://www.racetechnologies.com/imag...ype-bobbin.jpg http://www.racetechnologies.com/imag...ype-bobbin.jpg
http://www.racetechnologies.com/imag...ware-250px.jpg

The floating 2-piece anti-rattle disc hardware system, commonly used in high performance braking systems, was actually developed by Brembo back in the mid 90's.

This innovation was initially engineered exclusively for the McLaren F1 supercar which is why the hardware is often nicknamed the "McLaren" spring.

you only need 4 for each disc the silver part in this picture and the square part on the d-type bobben or a small washer will do

I thought I'd provide an update on this. I had a good look over my Alcons and couldn't find any play that would cause the type of noise I'm experiencing so I spent a further evening under the car with my rubber mallet, crowbar, and screwdriver, knocking and prying at everything I could think of.

And....

I 'think' I've tracked the noise down. It's coming from the inner pads on my rear brakes. They are just sitting loosely in the calipers and can quite easily rattle up and down. A quick Google shows that this is not such an uncommon event so I'm going to spend this evening pulling the rear calipers apart and seeing what the score with my pads are. I will report back.

I had exactly the same issue with the rears on my AP set up, at low speeds it sounded terrible. Anti rattle clips were installed correctly but I was advised these can lose their tension after a while.

In addition I found that AP make what looks like a small foam sticky shim which I had fitted and which in addition to replacing clips with new ones have stopped the rattle.

The shims were pence to buy, one of the cheapest mods ever made!

Do you have a link or part number for the shims? TVM :thumbs:

my APs have never rattled :smokin:

I will take a look at my invoice and let you know

So mystery solved. Both of my inner rear pads are missing the spring that holds them onto the rear brake piston. As shown below:

http://i568.photobucket.com/albums/s...ps8lqk07yo.jpg

This leaves the pads free to rattle around in the callipers and create the noise I'm hearing. I'm kind of pissed about this as the pads have plenty of life left and being Pagid RS4-2s are not inexpensive.

So I have a few choices.

1. Live with the noise.
2. Replace pads with new set of RS4-2s
3. Replace pads with bogo Pagids from Eurocarparts.

Option 1 isn't really an option but I'd happily go with option 3 if I thought I was't going to notice a major loss in stopping ability. I do plan to do a few track days this summer but probably no more than two or three. Is splashing the cash an a new set of RS4-2s worth it and if so where do I get them? A quick Google and it seems front pads are easy to find, rears less so.

I'd leave it as is.

I've come round to your way of thinking Paul. I never noticed the noise as I blasted up the Lecht on Sunday evening.