Brake pad and sensor replacement questions - BMW Forum

Lotusj · 11-28-2012, 02:16 PM

I have a 2008 E92 sport with 50K miles. I bought last month and only driven about 2000 miles.

I want to replace my front brake pads with akebono pads to reduce the dust issues I have with the current pads. I have been reading the forum and trying to understand when and when not to replace brake pad sensors and when and when not to reset the CBS. It’s a little confusing so I am asking for your advice.

I learned that the brake sensor has two stages. Once the first stage starts the CBS starts estimating the pad life and starts to decline until the second stage is started and tells you its time to replace the pads.

My service info, service requirements screen on I drive tells me front brake life 38000 and rear 20000 and this has not changed at all since I have been driving it.

Here are my questions:

1. When you reset the CBS what mileage shows up in the service requirements screen? Have I started the break sensor CBS count down yet? (Remember it has not changed in 2000 miles)

2. Can I change only front pads and reset front brake CBS setting? Should I change sensor if it has not started to wear? Some say do it some say no you will mess up the CBS.

3. How do you reset CBS?

4. Do I need to (should I) just replace front and rear pads and sensors reset the CBS and be done with all the guessing?

Thanks in advance for your advice.

John

Lord Vader · 12-02-2012, 01:57 AM

Im not to familiar with the E90 platform, so I can tell you how it works on the E36/46. The sensor is located on the right front brake pad, and not both. Theirs one on the front, and one on the rear. On the E36/46 the sensor is only tripped telling you to replace the pads when the pad material reaches a certain thickness.

Im not a big fan of iDrive because sometimes those milage counters are wrong. The best and foolproof way to tell is to take the wheel off. If you only have 2-3mm of pad left, then you better get on replacing them. The front brakes are a 66/35 brake bias, so the front brakes usually wear out twice as fast as the rears.