Is there a simple way (not removing the pads) to measure brake pad wear (how much pad is left)? I remember reading that there was an expensive BMW tool that gave a reading of brake pad thickness but I am looking for a lower cost alternative. I know that you can eyeball it (replace the pad when it is as thick as backing plate), but I am trying to predict
wear for track day planning.

If I could find out what stock pad thickness is when new, be able to measure my current thickness, I'd be able to take a guess on how much longer (or how many more events), that they would last. The last thing I'd want to do is have the "replace pads" light come on after the first run.

 

If you are going to do a track day. Don't skimp on brakes.

Jack up your car pull the wheels & have a good look at the brakes. For the brake light to come on the pads have to be very thin. I wouldn't recommend using pads that are down 50%.

One other thing. If your brake fluid is more than a year old, change it to a high performance fluid. I like ATE Blue.

Have fun at your track day.

 

Thanks for the reply Crashton, but that is what I am trying to figure out. How do I know when the pads are 50% worn? I didn't look at them when they were new (had no idea I'd get into tracking and autocross) so I have nothing to compare them to.

 

How many miles on your car as of now?

I've got a set of pads I can measure for you tomorrow.

 

I have 26k on my 05 MCS and started tracking in 2/07. 7 track days to date. Had the dealer look at my pads after the 6th day. He reported I had 8mm left from 12mm when new. My car is stock with 16" wheels. So I guess I'm not going fast enough or braking hard enough to burn through the pads Now I'm just hoping to wear them down enough for the dealer to replace them this fall when my warranty is up!

 

IMO you shouldn't be going on track without checking your brake pads. Waiting until after the 6th track day doesn't seem like a very good idea to me. It's your call though.

You should be pulling the wheels & checking your brakes before every track day as a rule.

It's not only for your own safety, but also your instuctors & the others on the track too.

Just my .02 here.

Have fun, be safe.....

 

I have my slightly used pads from the 07 in the garage. The front pad measures 11mm of pad...so I'd probably buy the 12 as a starting point. I had about 1500 miles when I pulled the pads so figure initial break-in....For sure they are at least 11 new!

But more inportantly, wrt using the seat of the pants method of comparing to the backing plate I see the baking plate is 5mm. So swapping then is actually pretty conservative. I don't know when the wear sensors go off...I've yet to work on a car where the owner waited that long! but some have said the pad gets 'pretty thin' b4 the sensor is activated.