Brakes pulsating!?! - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Perfectlap · 01-25-2005, 09:24 PM

Driving home tonight I quick got on the brakes and got a weird pulsating vibration coming from the brake pedal that prevented the brakes from fully engaging.

This can't possibly be the ABS engaging?
It felt as though something was stuck in between the brake pad and the rotor.
Got out and did the visual check, didn't see anything but it was too dark.
Noticed this once before but I thought it was because I had my foot slightly on the clutch pedal at the same time. (Although "both feet in" as they after a spin should never be a problem) This time my foot was nowhere near the clutch but I was driving over some long patches of snow and sleet.
Wondering if I should have it towed to the dealer tommorow.

Any of this sound familiar to anyone?

Tool Pants · 01-25-2005, 10:31 PM

Sure sounds like ABS to me.

Perfectlap · 01-25-2005, 10:54 PM

ok the ABS kicking over sand and snow makes sense since I have no grip to begin with. But does the ABS usually kick in during sudden dry surface braking? and is ABS unaffected by the clutch engagement?
I'm wondering how this is going to feel like when Autocrossing/track, I'm used to stopmping on the brake and locking up often. With ABS It feels like the car just doesn't want to stop quickly!
A few times recently the ABS kicked in and I wasn't really going that fast.

Is this often traction control initiated ?

gardjea · 01-26-2005, 02:47 AM

Had the same issue with my 986 S ... when breaking with a road surface no perfect ( kind of small waves) the ABS was reacting in a strange way . With my new 987 it seems that thy corrected this issue .
JMG

Perfectlap · 01-26-2005, 02:21 PM

I've driven many cars and none ever felt this way (like a rock was stuck in the rotor). Does the PASM bypass ABS? Or is there any way to switch off the ABS and allow locking up? I'm only interested in doing this when driving competitively.

By the way does anyone know of a good link that explains the Porsche ABS?

Jeannot · 01-26-2005, 02:25 PM

PASM? You talk on a 987 here or are you talking 986?

saphriel · 01-28-2005, 11:06 PM

Hi,
I'm guessing you might have already considered this, but...
are any of your rotors possibly warped?
It can only take a few millimeters (and so isn't too visible by inspection), but that would be enough to cause a generous amount of pulsing.

Regards