At this point - secure bleed nipple and if the reservoir is low put enough fluid in to ensure there is no chance of air getting into the system.
DO NOT FILL TO THE TOP - the next steps involve opening up the brake pads - this will force fluid up into the reservior - if it is full you will have a mess. As a point of interest the above pictures shows how much fluid I had when I secured the reservoir nipple.
NOTE - the tightening torque for the reservoir nipple is 2Nm - I set it hand tight.
The next steps in fluid replacement for the front brakes are to replace the fluid in the calipers and lines.
To do this BMW uses some really cool tools to push back and hold the pads open to push out the fliud.
If interested the tool part numbers are 341531 and 341532 - as I have no intention of getting these tools, I subsituted by removing the calipers to push back and hold the pads in place.
Now that both calipers are held open you can begin vaccum bleeding the caliper.
The set up I used is shown below.
You will need an 8mm wrench for the caliper nipple.
FLUID REPLACEMENT PROCESS -
1 - Remove fluid from reservoir on handle bar and replace with new fluid
2 - connect vaccum device to bleed nipple
3 - open bleed nipple and start vaccum
4 - check fluid level in reservoir - do not allow to drain completely
5 - continue steps 3 and 4 until clear fluid is being extracted.
6 - close off bleed nipple
7 - top off reservoir
Repeat for other side
PROCESS NOTE 1 - as a personal preference I remove the rubber nipple covers to be able to properly access the nipple.
PROCESS NOTE 2 - the standard tubing included with the Mighty Vac - fit ok onto the nipple but not snugly enough to prevent asmall amount air leakage - when extracting the fluid there were some bubbles noted in the stream. For next fluid replacement I will get some smaller tubing for a snugger fit. The tubing ID use on the front reservior was too small for use on the caliper nipple.
1 - connect vaccum device to bleed nipple
2 - open bleed nipple and start vaccum
3 - check fluid level in reservoir - do not allow to drain completely
4 - continue steps 3 and 4 until clear fluid is being extracted.
5 - close off bleed nipple
After mount the calipers back onto the fork tubes.
The closing portion is to do a manual bleed of the front brake at the caliper - this is to ensure no air managed to enter the system during vacuum evacuation.
Process for Right Side Manual Bleed
1 - Pump lever a few times (3 to 4 times should be enough) until you have solid resistance.
2 - while maintaining pressure on the lever - open the bleed screw slightly - and observe color of fluid being expelled
3 - tighten the bleed screw BEFORE LETTING GO OF THE LEVER - I can not stress this enough as there is a potential for air injestion.
4 - Repeat steps 1-3 until clear fluid is extracted - please keep an eye on your reservior fluid level.
NOTE - It took me 3 repeats of the above steps to get clear liquid - this is not to say to do it only 3 times, but rather it did not take many repetitions to achieve the desired results.
Process for Left Side Manual Bleed
Note - it is extremely helpful to have an assitant support you in this actiity - they can do the hand lever and watch the fluid level, while you do the bleeding at the caliper.
1 - Pump lever a few times (3 to 4 times should be enough) until you have solid resistance.
2 - while maintaining pressure on the lever - open the bleed screw slightly - and observe color of fluid being expelled
3 - tighten the bleed screw BEFORE LETTING GO OF THE LEVER - I can not stress this enough as there is a potential for air injestion.
4 - Repeat steps 1-3 until clear fluid is extracted - please keep an eye on your reservior fluid level.
NOTE - It took me 3 repeats of the above steps to get clear liquid - this is not to say to do it only 3 times, but rather it did not take many repetitions to achieve the desired results.
Close off caliper bleed screws. - BMW stated torque is 5Nm - I did them hand tight
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