why isn't miles to brake service.changing?

[lanbrown]

With 1,200 miles listed by the CBS, the first part of the sensor should have been tripped. Once the sensor is tripped, I would expect that the system has a much clearer picture of pad life left. I believe the sensor is tripped when about 2,000 miles are left on the pads. The question would be, right before it tripped, did CBS state 2,000 miles or some other value?

[Davidf]

Always a good idea to inspect. I purchase a 2007 328i for my son. Pull the wheels to check the brakes and the front wear sensor wires were wire nutted together and wrapped around the strut. No sensor at all!

[Ron07x5]

I will inspect this weekend. BMW service record show the front brakes and rotors where done 30k ago and the rear brakes and rotors done 50k ago.
It is remotely possible an amateur mechanical friend of the owner replaced the rear pads, and I can believe he might have left the sensor wrong there but it doesn't explain the front brakes which I can't believe after just 30k would need changing in less than 5k. This why I posted about this something doesn't make sense with the cars stats. Well I will inspect and sort it out and report here. Sounds like a sensor may be worn ... but those I believe were replaced by bmw when bmw did the brakes.

[ard]

Originally Posted by Ron07x5

I will inspect this weekend. BMW service record show the front brakes and rotors where done 30k ago and the rear brakes and rotors done 50k ago.
It is remotely possible an amateur mechanical friend of the owner replaced the rear pads, and I can believe he might have left the sensor wrong there but it doesn't explain the front brakes which I can't believe after just 30k would need changing in less than 5k. This why I posted about this something doesn't make sense with the cars stats. Well I will inspect and sort it out and report here. Sounds like a sensor may be worn ... but those I believe were replaced by bmw when bmw did the brakes.

I did 40k on fronts, 55k rears.

The sensor is not a 'meter' that measures wear. There are two contacts that get 'broken' as they wear- the computer int he car uses the first 'break' to adjust the multiplier on its internal wear calculation- then when the pad is fully gone the second sensor is broken. You get a "brake service due" red indicator for that.

As above, do not assume the dealer or whoever replaced the rotors or sensors as they were supposed to...

[Davidf]

30k miles is about right on OEM pads.