Brake pad wear
 

History - 2005 Boxster S, purchased Apr 2015, great service records. Ran about a dozen auto crosses and 2 HPDEs, brake wear indicator lit up, replaced rotors and pads (EBC Yellow) at all 4 corners on January 30th. HPDE x 3 at Laguna Seca, 6 auto crosses, total of about 5 K miles since. Replaced tires, had 4 wheel alignment (more track oriented/less street requested) and some other work at my independent shop last week. They told me my brakes had plenty of life left - I also did a pre-HPDE visual and confirmed this.

Last Saturday and Sunday I ran the Thunderhill 5 mile track, HPDE A group as first time on this track - skid pad, figure 8, etc. both days, and on track passing exercise, etc. so I only had a few laps each day of fast runs. About 10 minutes into my 3rd session Sunday my brake wear indicator lights up.

I ordered pads Monday, they came in yesterday, pulled 1 rear, doesn't need replacement. Pulled the front on the same side - outer pad is worn just about to the sensor, inner is at about half life. Pulled the other side front tonight, both pads at about half life.

Do I need to have the caliper rebuilt? Should I just clean it up good and keep an eye on it? Anything else I should be thinking about?

Thanks,

Mike

How long since the brakes have been bled?

I bled them 2 weeks ago. I bleed them the weekend before every track event.

Rent out Laguna Seca (inviting me at no charge off course :D) and run it backwards for a day/weekend with fresh pads and see if other side's outer front wears as quickly... ;) Could you imagine running UP the Corkscrew???

Just kidding...

Inner pads typically wear faster than outers. Since (by your comments) other 3 front pads are ~ 50% life (and rears not needing replacement either) you likely have a problem w/ that caliper dragging/stuck. There's ~ 25% meat left when sensor is triggered meaning that pad is wearing 50% faster than others. If both pads in same caliper were even you could pull in ABS and/or t/c as possibility but since only one... caliper is very suspect. How was wear across worn pad itself - even?

You can try pulling and inspect pistons etc. but likely a rebuild will be your solution and might as well do both fronts at same time.

Good luck :)

Do you ever notice any difference between the right and left side? Any pull to one side? Can you hear the pad dragging on the rotor or can you feel a difference in resistance when rotating the wheels (on lift or jacked up)? I would expect there to be some kind of noticable physical symptom with that much difference in pad wear.

With that being said, it certainly points to the calipers and as Burg suggested, do both at the same time.

The pad wear is pretty even, within a few thousandths all around.

I didn't notice any pulling, or drifting to one side. A few times over that last month or so I thought I may have heard something from that side of the car, but turning down the music and listening for anything never led to any definite new sound from that side. I was always in traffic, at low speed in town (< 35 mph) whenever I thought I heard the noise. I was thinking wheel bearing for the noise, so I made sure to really feel for play in several spots on my pre-track day inspection, all 4 wheels had no play at all.

I ordered the rebuild kits today. I have several things coming up, so it will be a few weeks before I ca get to them.

Thanks for the advice all.

Up the corkscrew....hmmm.....

Once you get faster and start putting more heat in the brakes you will melt the sensors in a regular basis, giving you false brake wear dash lights. Happened to me coming down the hill after the back straight at road Atlanta and freaked me out big time... I have all four of my sensors cut off and twisted the wires together. I figure I am in there enough to where I can visually check them...

I've had my wear sensors light up twice now - both times on track. The first time was at Laguna Seca, I noticed it dropping down the cork screw; it was my second track day ever, 4th session of the day. That one freaked me out pretty good.

Thunderhill has a corner they call "the Cyclone", I think it was modeled to simulate the corkscrew. Very fast uphill, blind left at the crest, dropping through a right hand turn. I noticed the brake light on about 2 seconds from the brake point for the blind left. It didn't freak me nearly as much this time. I got over the crest, told the coach riding with me that I had a bake light on, and proceeded as normal. He had a lot of questions - brakes feel sloggish, feel crunchy, etc. No, No, No...could be a wear indicator but they looked good a couple of days ago.... Told him I would back out of it a bit for the rest of the lap, for which he was grateful.

We don't ne no stinkin brake wear sensors!
Cable tie then out of the way

Did someone say http://986forum.com/forums/performance-technical-chat/29933-melted-brake-sensors.html#post408914?

http://i1114.photobucket.com/albums/...nsorMelted.jpg