Brake Pad warning light - What's up with that??

[jog5000]

While out driving today, my brake pad warning light came on, and of course I though "Oh SH*T". And then about an hour later, while still driving, trying not to brake at all (rather difficult in traffic on the M25) the light went off.
Then when I went to the shops earlier this evening, it came on again, then went off ten minutes later........ any ideas?
Going to get my pads changed tomorrow anyways.....

[johnono]

have the same (ish) prob as you, check to see if theyԚ´re plugged in though

[irishstevo]

This is a common enough thing . Check both the front left and rear right pad sensers for a broken wire . They can be either soldered up or as i did , taped back up . If you don't want to use the sensers at all , just tape the 2 wires together and the dash light will go out .

[Brianmoooore]

No need to panic into changing the pads. Only one pad of the four at the front ( and the same at the back, if you have rear discs ), is fitted with a wear sensor. Pads don't wear completeley evenly, so to be on the safe side, the light usually comes on when there are several thousand miles of wear left in the pads.
You should have a look at the pads though, to check that none are nearly down to the metal. There is also a much discussed fault in the instrument cluster that puts the pad wear light on intermittently. ( Do a search for 220 ohm resistor).
Check the condition of the discs before you change the pads as well. E30 discs only last the life of two or three sets of pads.

[jog5000]

Had a look at my discs today, and they were good. Spoke to a guy at the brake change place, told him my light came on, he says that I have perhaps 100 miles before I start grinding my discs... any truth?

[johnono]

how hard do u break?

[jog5000]

I generally use gear braking, on the odd occasion I do have to hit the brakes, but on average not hard

[johnono]

can u feel any slight juddering in your foot on braking

[jog5000]

no juddering at all....... brakes as smoothly as when I got the car

[johnono]

so u got time then, if you can do it sooner than later its best in the long run, wont carve up your discs

[jog5000]

well, I'm going to get it done tomorrow. Just wondering whether I should pay 40 quid and do it myself, or spend 80 and have it done by someone else.

[johnono]

well if u can do it, then its a silly question init

but if you feel safer, (i wouldnt do my own) then 40 for peice of mind cant be too bad

[Brianmoooore]

If you've checked your discs properly, you must have taken the wheels off, (it's cracks and thickness of disc that matters). You can see the state of the pads by looking at the disc edge on through the caliper.
When the pad light comes on there is at least a thousand miles of braking left in the pad that has the sensor, assuming it's worn parallel to the disc. This pad may not be the most worn of course, but this can only be checked by examining the pads as above.

[johnono]

thats what i did too

[Brianmoooore]

Johnono - You've much more faith in the skills of the average grease monkey than I have. Peace of mind is exactly the reason I would change my own discs and pads.
From time to time I buy written off BMWs, and you wouldn't believe the standard of servicing work I see on most of them.

[johnono]

i beleive you man but iԚ´d spent all day wondering if i did it right

so i,d probbably hang around the garage and be `interestedԚ´ alot

[jog5000]

Well, after reading the Haynes, I'm pretty sure I can do it myself, its just the question of "did I do it right".........
Any tips?

[Brianmoooore]

Threads on the end of the caliper slides are fairly easy to cross thread, and check that both wings of the pad springs are held by the caliper.
A LITTLE copper grease on the back of the pads, and their contact points to the caliper stops brake squeal.
The best way to push the pistons back, is to open the bleed valve slightly and let the fluid escape as you do so.
Pump the brake pedal before you drive off afterwards to push the new pads up to the disc. You wouldn't be the first to find you have no brakes the first time you need them after changing pads.

[jog5000]

Thanks............. What is the most difficuly part about doing it?