Front pads

[Timdon]

Hi has anyone got a link to changing the front brake pads on a 35i ,the light has just come on ,is it an easy diy job?

[Gaffa22]

Yes quite straight forward, only special tool you need is a 7mm Allen male socket
You haven't said which model you have and there are a couple of different calipers but have a look here

https://www.newtis.info/tisv2/a/en/e89- ... s/8JLCoH8q

[Timdon]

Thanks a lot gaffa

[Timdon]

Do I have to replace the sensor? Or can I just replace the pads.

[synthedup]

Do I have to replace the sensor? Or can I just replace the pads.

You need to replace the sensor

[Gaffa22]

As synthedup said, yes if the light came on then the sensor is knackered
They are about £8
Use ceratec grease not copper slip.

[flybobbie]

My advice now would be to fit a new sensor and reset the wear indication. You can always thread the new sensor down when fitting new brakes. If you go a few hundred miles or it goes -ve value with the warning, you might have a load of hassle going to a garage to reset, as a few of use on hear can testify to, end up needing something like a Autel reset tool.
It's plug socket is next to the left strut under the bonnet.
Personally i have not connected any of the new wear sensors to the brakes, due the hassle, they are tied back, i monitor by sight.

[Gaffa22]

That's interesting flyrobbie, if you are going to tie the sensor back do you actually need to replace the sensor if the warning light has come on. Or does the light go out as soon as you break the contact between sensor and disc.
When I was cleaning and painting my calipers I lost one of the little U clips that hold the sensor to the pad, I had considered tying it back as I am happy to check by sight, was about to reach for cable ties when I spotted the clip, so refitted it.

[Silverzedtom]

Yes quite straight forward, only special tool you need is a 7mm Allen male socket
You haven't said which model you have and there are a couple of different calipers but have a look here

https://www.newtis.info/tisv2/a/en/e89- ... s/8JLCoH8q

Don’t forget you will want a rewind tool to push the piston back as well, a G clamp or similar might work instead.

[Timdon]

Thanks for the replies.the light comes on telling me the pads need replacing but the idrive says they have 20000 miles left,is it common for the sensors to fail ? Or would you replace the lot
Many thanks.
Z4 e89 35i. 2012 .

[Gaffa22]

Whip the wheels off and have a look at the pads. They'd be quite thick if they have 20k miles left in them.
Where are you based Timdon ? I'm near Norwich happy to look at it for you if you're near enough.

[Timdon]

Thanks but I’m up in Yorkshire I will take the wheels off and have a quick look it was easy on the S 2000 but they didn’t have a sensor

[Gaffa22]

Ah yes thats a bit too far away.
No more difficult on the Z4, I also had an S2000 before the Zed, don't think i've had a car with sensors before so not really bothered about them to be honest, i'd rather check by sight

[flybobbie]

Need to fit a new sensor then reset through the stalk, plenty of vids on youtube.

The sensor seems to have two levels where a wire shorts. Only a two wire system.
You reset then it measures how many miles to first contact then tells you how miles left to wear out. Then the second contact tells you the pad is worn out, even though it might say 20k left. Someone has done some heavy breaking or unusual disc wear.

Keep in mind some clever dick at BMW has worked all this out, not for your benefit, but there so they don't have to service too soon.
(Yeh good for another 20k, the techi said).

[Nictrix]

The sensors are there to make money from people who know nothing about cars.
The light comes on in the car and the owner then asks the garage to replace the brakes.
The sensors trip far too early, sometimes with more than half the pad material left.
A new sensor is not always needed as with our old Mini I just bared the wires and connected them to each other and tied it out the way and this was enough. If you are not going to use the sensor why bother buying a new one.