J.G. Rausa

While on a drive yesterday, I noted a grinding noise when applying heavy brake pressure. Not so much "noise" using light pressure coming to a slower stop. Once home, I removed front right pad and noted thickness down to less than 11mm, stock S pad is 16.8mm. It would appear as though the pad sensors begin to "wear" once the pad is down to about 10 mm - note the "hole" for the wear pad indicator on the first pic. The second pic shows the cutout for the sensor wiring in the backing plate just above the indentation in the upper radius of the pad where the indicator is positioned..

The question becomes, do you change the pad now or wait till the wear pad indicator sends its message to your dash?

For me it's an easy answer - based merely on cost. The wear pad indicators sell for about 30% of the cost of the pads. If I can reuse the indicators, I can save myself some coin - as long as they are reusable and I don't break them on the pad change. I figure I'd blow through the <1mm left to the indicator at the next AX event.

The grinding noise? I'm not certain, but there was a slight crack in the pad above the sensor. I think that when applying "heavy" brake pressure, the sensor was creating a high spot on the pad. Either that or the other front pad has worn into the sensor and that was what I was hearing. I'll know once I swap out the pads.

Joe
2011 997 GTS - 13,200 miles (includes 7 DE events - not bad for a stock set of front pads)

LexVan

You can just zip tie the sensors out of your way (save the $39/set) and change pads when needed. They often break when doing pad changes. And if you are going to be doing a lot of DE events, look into Pagid pads.

Ptech1

+1

Sensors are there for those who need to be reminded not to wear through the rotor. And they will not come out intact after being heat soaked.

function12

If you are replacing pads then I would buy at least one sensor wire. You are bound to break one or see one that needs to be replaced. It's better to have the part in hand then to re-do your work for just the sensor.

USMC_DS1

+1... sensors are fragile and known to break during a brake job.

stronbl

^^^+1

Rear sensors will break easily; front sensors usually can be reused unless wear indicator was triggered. You may need Durametric or PIWIS to clear the sensor indicator notice on the instrument cluster if you do not reconnect/install.

Macster

When doing the brakes on my Boxster I've reused the sensors. I've never had one break when taking the pads out and removing the sensors from the pads.

In fact I can't even remember if they were that difficult to remove the pads but I think not or I would remember, or had one break and I would remember that too.

Unless you track the car and are at the brakes frequently my advice is if you do not want to risk reusing the old sensors is buy new sensors.

In the overall scheme of things that are not that much money and I like to have to not worry about when the pads are worn down to the point they need replacing.

Now you can reuse the old sensors. But a word about this. Whenever I have done this I have done it with the knowledge that should the sensors prove to be a problem in some way that I would have to buy new sensors and go back and replace the old sensors. But to me this is not a real show stopper. It is a gamble I'm willing to take.

7500rpm

Joe,
Sounds like you are quite a regular at DEs. I would go without the sensors or you will be wearing away lots of coins. As Ptech1 says, I agree that they are for people who needs to be told that their pads are done. We run thru pads significantly faster and need to be checking them regularly anyways. Or you should at least be changing fluids after 4-5 hours of hard driving and you should be checking your pad thickness then. However, not having the wires in place cause the brake pad warning light to come on. You could zip tie the wire away as Lexvan suggest (assuming the sensors are still fine) or you can 'hot wire' a sensor that's already been worn through. That should turn off the lights and I don't think you need a Durametric or PIWIS.
As for Macster's comments, I think he is an alien from another planet. IIRC, his clutch lasted him 285,000 miles and still had life in them. I really would like a video recording of how he drives. Its not surprising then that he has not broken any wires and just continue to reuse them. Mine came off the pads as ash ........

997_rich

+3(?) on don't need them. I cut my sensors off, bridged the wires, soldered, shrink wrapped so i don't get the idiot lights. The best brake sensors are your eyes.

J.G. Rausa

Replaced front pads today. I was able to reuse sensors as they removed from old pads and installed on new pads without drama.

Below is pic of the source of "grinding" noise. Driver's side pad began to wear on sensor, but didn't rub through.

Moral of the story - listen to those "not quite right" sounds and your car will tell you when it's time for service.

Thanks for everyone's responses/tips.

Now to bed in the pads.

Joe