Hi all, grateful for your thoughts on this one,

my S (2007my) has developed a strange braking problem, it's in the dealers at the moment, who are, I'm glad to report, keen to help. Here are the symptoms (at first I thought a warped disc but it doesn't seem that simple):

- Under braking the whole car is vibrating with some vibration through the steering wheel but mainly through the brake pedal. No loss of stopping power and the car remains stable and brakes in a straight line. This generally happens from 40 mph upwards but is more pronounced braking from 70mph.

- Heavy and loud 'rumbling' noise under braking.

- Feels like the problem is at the front of the car.

Over the past 3 hot days this has happened consistently, which had me thinking warped disc, but:

- Does not happen initially in damp/wet conditions (misty here this morning) to the extent even braking from 70+ there was no obvious issue for the first 10 miles this morning. (Problems never happen when you take the car to the dealers do they!!)

- Starts to happen when the brakes get warm, is much worse when they are hot (eg heavy braking off an m'way slip road), continues at all speeds until the brakes cool again.

I'm sure the dealer will sort out the problem but if anyone has encountered similar problems and we can help them sort it quicker all the better.

Thanks,

Mark

 

Sounds like warped discs to me, when cold they are within tolerance, as soon as they heat up the issue is exaggerated.

 

MBK haven't you just done a series of track days? Could you have warped your brakes, or done some other damage to them?

 

Sounds like warped discs to me too. With lighter braking the sliders and piston can accommodate a bit of warping, but when things get hot the warping increases and you get the problem you describe.

The other possibility is pad adhesion or uneven wear on the discs.

Either way, the dealer should be able to check for run out on the discs and see it quite easily.

 

Another one for warpage.
When it's hot is may be "more" warped due to the thermal difference

 

Ok that makes sense, they are checking it out now, new discs and pads then. And a good excuse for an upgrade in the next week or two (the modding bug begins...)

As for the cause it could have been a number of things, I suspect the trackdays played their part! The problem first happened last week after having to break heavily on a motorway slip road, cold morning/heavy braking combo.

I would have hoped for a bit more resistance than this from the standard brakes (they certainly feel up to the job), the only car I've had this problem with before was a modified Impreza. No complaints though because I freely admit I like to use the S as the designers intended.

The service manager commented this morning that I was the only customer he knew who actually used the performance of the S, most he said are "driven at about 25mph"!

I will let you know the outcome.

 

If it is warpage I'd suggest you reconsider your cooling down practises @ track days

 

Yep it's warpage, pads and discs required.

As for cooling down, I learned that lesson from Impreza days so I always do the final lap without touching the brakes and a good slow run around in the paddock afterwards/no handbrake etc so shorter sessions out is probably the only answer. Just a problem caused by getting quicker/braking harder/later I suspect.

No big deal imo, to be expected if it's driven. Any suggestions on upgrading the discs/pads I have found the Disc Brakes Australia slotted discs with uprated pads effective in the past.

Don't want to go as far as the AP/Brembo big brake conversion yet. By my quick reckoning it would be cheaper to buy an Exige S than turn the S into a real track toy!

 

DBA4000 series discs are good with ferodo DS2500 pads.

No warpage for me yet. Every other disc i tried with the ferodo pads warped or cracked.

 

It may be cementation (black rings of melted & re-hardened brake pad material) on the discs.

Track days.

I emeried the cementation off mine and they were fine. Wearing a bit thin now (40K) but no warpage, unlike the Civic and the 'Lude.

But the Civics are a bit too small, really.