[FirstBMWLA]

Recently got an 18 440i with 12k miles
Had a message for upcoming service around 14k miles for brakes
Now at 13800 the brake indicator for rear pads has tripped.
seems really early huh? My 07 335i went to 75k without tripping indicator.
Guess I need to dig up a DIY for rear pads and sensor.

[cfm56d7b]

How much stop and go driving does your vehicle drive endure?

This might be a sensor - the mileage is quite low.

[FirstBMWLA]

Originally Posted by cfm56d7b

How much stop and go driving does your vehicle drive endure?

This might be a sensor - the mileage is quite low.

Commute is city driving. average speed 35
I haven't driven hard at all.
No clue how it was driven beforehand though.
Just shocked at low miles.
Once brake light is tripped on dash sensor must be replaced right?

[FirstBMWLA]

Headed out of town for weekend
About to order Powerstop pads and sensor part number 34356792292 off Amazon.
Ship to my in laws house and we'll have a DIY weekend I guess and sort it out.

[Billfitz]

Originally Posted by FirstBMWLA

Now at 13800 the brake indicator for rear pads has tripped.
seems really early huh?

Mine tripped at 11k:
http://f30.bimmerpost.com/forums/sho....php?t=1471617

[FirstBMWLA]

Originally Posted by Billfitz

Mine tripped at 11k:
http://f30.bimmerpost.com/forums/sho....php?t=1471617

crazy!
Pads aren't covered under warranty right?

[Billfitz]

In my case they should have been, as they wore out early due to a defect in workmanship. I didn't bother to investigate it, it wasn't worth it to me to spend a day driving to and from the dealership to get it done.

[FirstBMWLA]

Originally Posted by Billfitz

In my case they should have been, as they wore out early due to a defect in workmanship. I didn't bother to investigate it, it wasn't worth it to me to spend a day driving to and from the dealership to get it done.

Tough argument to win with dealers.
I hear ya on the not worth it
Ive done lots of DIYs before like water pumps and fuel pumps etc but never brakes.
Time for me to learn. Figure can't be that hard.

I'm trying to visualize the problem you described with lack of grease on pads but having not worked on them I can't quite.
I suspect maybe I have same issue you had.

[Billfitz]

The pads are held in place on either side of the rotor by the pad carriers. The caliper squeezes the pads against the rotor, that's what brakes the car. The pads have to be able to slide in the carrier just freely enough to allow them to press hard against the rotor when braking and release when not braking. If the pad to carrier interfaces aren't properly greased rust can develop. If the rust is serious enough the pad won't release from the rotor when the brakes are released, causing premature pad and rotor wear.

[FirstBMWLA]

Originally Posted by Billfitz

The pads are held in place on either side of the rotor by the pad carriers. The caliper squeezes the pads against the rotor, that's what brakes the car. The pads have to be able to slide in the carrier just freely enough to allow them to press hard against the rotor when braking and release when not braking. If the pad to carrier interfaces aren't properly greased rust can develop. If the rust is serious enough the pad won't release from the rotor when the brakes are released, causing premature pad and rotor wear.

Great explanation!
I appreciate you taking the time.
Why I love these forums.

[John in VA]

From the online BMW repair manual (TIS):
Rear pad replacement:
https://www.newtis.info/tisv2/a/en/f...rakes/Gu44qNBI

Sensor replacement:
https://www.newtis.info/tisv2/a/en/f...cator/GfosboZT

I did this last weekend - it was a breeze.

[FirstBMWLA]

Update:
Got rear wheel off and checked pads and sensor.
Pads seem fine but something has hit the wiring of the sensor and cut through insulation.
I suspect that's why I got the light.
Procedure mentions filing down the sliding contact if replacing sensor only.
With pads being so new hopefully I don't need to worry with that.