just had a nice warning message pop up on my zed today, which the handbook says brake pads need to be replaced (red inspection symbol and warning (!) symbol popped up on the dash) strange thing is that the computer says 8000 miles for the rear pads and 20000 miles on the front pads. Car is booked in for a look but just wondered why the early warning, its going to take me a while to rack up another 8000 miles.
Brake Pads
- Thread starter philabbo
- Start date
With your wheels you should be able to see how much pad you have left. Just be aware the inside pad you can't see may have worn a little more. I have had a few issues with the dash lights but have had the front sensor disabled now because I changed the callipers.
The rear pads don't wear as quick as the fronts, 5mm should last two weeks under normal driving, just keep an eye on them. Don't forget to barter them down on price for both pads and labour because it only takes them about 40 minutes from taking the keys from you to returning them.
The 'miles to go' is purely an estimation based on expected 'average' usage. The warning you're getting will come from the wear sensors embedded in the disc pads, which is 'actual' data and therefore far more acurate. My dealer told me that if they get an agressive braker that causes the brake wear warning to come on earlier than the estimated miles to go count, they would set the count lower after the pads were changed.
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The Wear sensor actually has 2 separate contacts. The first of which wears through fairly quickly and is used to give an approximation of the remaining life of the pads. The second is an actual warning that the pads are genuinely low. I now have access to the BMW ISTA/D software so can do a search for the explanation if required. Interestingly, it does also give full instructions on how to do a pad change without using the diagnostic system to wind the servos back. There is a bit more to it but basically it is a case of removing the servo and using a Hex Key to wind back the pistons.
http://www.z4-forum.com/forum/viewtopic.php?f=46&t=52614
When i have time, i wil disect my old pad sensor to see how it works.
One assumes that after the initial wear if you are more aggresive with the brakes you won't reach the computer suggested life.
Off course after the initial bedding in of a new disc, it becomes scored, reducing the life of the pad. Has the BMW computer model taken that into account.
When i have time, i wil disect my old pad sensor to see how it works.
One assumes that after the initial wear if you are more aggresive with the brakes you won't reach the computer suggested life.
Off course after the initial bedding in of a new disc, it becomes scored, reducing the life of the pad. Has the BMW computer model taken that into account.
I do know there is only two wires. If you join them together and have the car reset then the sensor system is disabled. This means they are joined to start with and as the pads wear the sensor wears too. The sensor may act like a two stage resistor to eventually show no connection, pads worn.
The suggestion is the first wire shorts out, telling the computer rate of wear. Then calculates how long before the second shorts out.
Seems to rely too much on on wires shorting out to disc.
Would seem simpler to program computer to to measure mileage to to twin wire break, then guess mileage to warn out. based on past experience. (Knowing BMW on the genuine side).
Personally by the time a set of pads are worn might actually need new discs. So why not run till audible wear.
Yes, i know some people to thick to realise that griniding noise is from worn out brake pads!
Seems to rely too much on on wires shorting out to disc.
Would seem simpler to program computer to to measure mileage to to twin wire break, then guess mileage to warn out. based on past experience. (Knowing BMW on the genuine side).
Personally by the time a set of pads are worn might actually need new discs. So why not run till audible wear.
Yes, i know some people to thick to realise that griniding noise is from worn out brake pads!
I thought and hoped it was pads and discs. I paid £290 for set of pads and disc on the front of my wife's Quattro. That sounds like a bargain now!
They even put a little tin of sweats in the glove box.
I think BMW have should take some lessons from Audi. ie an MOT costs £40 with an MOT warranty.
They even put a little tin of sweats in the glove box.
I think BMW have should take some lessons from Audi. ie an MOT costs £40 with an MOT warranty.
car is back, didn't realise how bad the speaker was until I heard the new one! car has got to go back though for a software update to fix the tappety cold startup noise on the 2.3 - 6 cylinder engine. To be honest its not really bothered me as it goes after a minute or two and silky smooth once warm, but worth getting done as its just an update.