Brake warning light kept flickering on and off for a few days. Because it went out when I hit the brakes and I knew the pads were okay I diagnosed low brake fluid levels.
As I haven't changed the brake fluid since I had the car I decided to do a full brake fluid flush. This meant buying some brake fluid and a flushing kit.
I had to buy a pair of axle stands as well because last time I had the car up on stands on the drive there was an issue with gravity caused by the sloping drive. Having had to jack the car off my legs once before I decided new stronger axle stands would be a good idea.
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WCA!, on Flickr
This time, to save my legs, I tried parking across the slope.
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WCA!, on Flickr
You have to do the back passenger side, then back driver side, then front passenger and then front drivers.
BMW decided that they would make the jacking point and axle stand point the same place so there was no way to jack up the car normally and place the axle stands. Instead you stick a trolley jack under the rear diff and go from there.
The slope didn't do wonders for the jacking angle but there was a bigger problem. This shows the trolley jack at max extension and with the car wobbling precariously on the lift. The left wheel barely leaves the ground.
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WCA!, on Flickr
I decided the safest and sensible way forward was to wedge a bit of pallet wood between the jack and the car to get the extra inches of lift.
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WCA!, on Flickr
It worked
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WCA!, on Flickr
The car was now in the air at the rear. So now lets look at the bleed kit and see what it contains. There are a selection of lids to fit the master cylinder (2nd largest worked for me) a selection of clear bleed pipes (middle size fitted for me) and the other bits all seemed to make sense.
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WCA!, on Flickr
Let's fit the kit!
Identify the brake master reservoir
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WCA!, on Flickr
Clean it a bit with some baby wipes to prevent crap getting into the brake fluid
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WCA!, on Flickr
Test fit the kit (really easy) and pressure test before adding any fluid
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WCA!, on Flickr
The pressure is provided by letting the spare down to 20psi and then connected that
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WCA!, on Flickr
No pressure leaks so add some fluid and connect it all back together
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WCA!, on Flickr
At the wheel end identify the bleed nipple (tee hee, I said nipple) and squirt penetrating oil all over it. This is the dark bit on the top right of the caliper.
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WCA!, on Flickr
Attach the correct pipe and feed it into a collection vessel. I just grabbed the nearest bottle.
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WCA!, on Flickr
Ease off the nipple taking care not to round it off* and some pretty shitty brown stuff will start flowing.
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WCA!, on Flickr
Quite soon the fluid will be a lovely clear gold or what ever colour fluid you are using. I saw a recomendation to change the colour of the brake fluid each time you do this so the change is more obvious. Might try that next time if I remember.
Tighten up the nipple (titter) and move on to the next wheel. Do the wheels in this order : back passenger side, back driver side, front passenger and finally front driver side. It is all to do with the distance between the master cylinder and the brake caliper.
*My brake nipples (I had stopped even smiling at the word by now) were totally seized. It would have been easier to hold the nipple and rotate the car.
I would STRONGLEY recommend that you buy 4 new brake nipples before starting this job. My nipples are shredded (giggle) after this work and will need replacing next time for certain.
Anyway, the brakes are still great and there is no warning light. Several stops from over 100mph (private road obviously) shows now fade or any problems.
Wear gloves and brake fluid is crap for your skin.