Brake Ware Sensors

[Jehu]

How do they work? Do you see a message in the console or do i hear like a chirping/whistling sound from the wheel when the brakes are NOT employed?

[Blitzkrieg Bob]

imbedded in the plastic tip of the sensor gets worn away by the rotor and breaks the circuit open, it triggers the warning on the dash.

If you want to see the warning, just unplug the sensor.

[Jehu]

Good enogh. I heard some high pitched whisle sounded like it was coming from a rear wheel. It went away it seemed when i hit the brakes but after a minute it went away completely and didn't return,may have just been a wheel bearing groaning after i took an especially hard fast curve.

[632 Regal]

say "brake wear" "brake wear" "brake wear" sensor. as Bob says, easy deal to replace, fronts with tires, rears need wheels removed for access.

[Jehu]

say "brake wear" "brake wear" "brake wear" sensor. as Bob says, easy deal to replace, fronts with tires, rears need wheels removed for access.

I almost bought a house in Ware,NH. I guess i never forgot the place.. This notwithstanding, how does replacing the sensor help unless i replace the pads too in which case i have to take the wheels off anyway...

[kesslerbmw]

How those sensors work is..

Basicly there is a circut which is not complete until you wear away the plastic with the caliper pushing it up against the rotor. The plastic wears off and the wires touch and make a complete circut which tells the dash to light up with "Brake Linings"

[Jehu]

So then you go look at your pads and judge if you want to change them or like to like dangerously?

[Blitzkrieg Bob]

the circuit is closed until the fine wire gets worn away by the rotor, and becomes open.

That's why so many of us experiance false warnings from corrosion in the plug terminal.

[632 Regal]

they sometimes wear one side of the pad more than the other, you definetly should take a peek at them. I had no brake warning but the pass side was almost at metal to metal. Saved them rotors and was good to go.

[Blitzkrieg Bob]

there's only two sensors, one front one back.

so, if you got uneven wear, you got trouble.

[Jehu]

The guy i bought it from put new pads on in April . I've put about 6,000 miles on it . If they're worn enough to replace already i guess my rotors are hooped.

[gale]

There are only 2 sensors, 1 on the inside pad of the left-front, and the other on the inside pad of the right-rear, so they're only accurate if all pads are wearing evenly, as already mentioned. The nice thing about e32/e34 brakes is the outer edges of the pads are recessed slightly and don't go clear out to the o.d. of the rotors. You'll notice there is a slight ridge on the outer brim of used rotors, and if they do end up going metal on metal, it's the pad's metal backing rubbing on the ridge, and not the braking surface itself. You do have a grace period when you hear the squeal, before damage is done. I would tend to it within a few hundred miles if that's the case.

[Jehu]

Like i said the squeal didn't really sound like other clips style brake wear sensors I've heard and disappeared after a minute. I thought there might be like an audible electric things that goes off or something . I'll check the pads tomorrow but they've only got 6,000 miles on 'em . If they're already bad I'd be disgruntled..