I need to drain the brake fluid for my 1999 BMW K1200RS with ABS in order to do some minor service on the Master Cylinder, but I don't have a service manual for the bike. How should I go about doing this, and what are the things I need to watch for?

Also, presumably, at some point I'll need to put brake fluid back in the bike. How do I do this as well?

  • Just a note about brake fluid. Don't get it on the bike! It strips paint like you wouldn't believe.
    – Kendrick
    Commented Mar 8, 2011 at 16:24

2 Answers 2


Factory service manuals are usually expensive and they assume you already know how to fix motorcycles and have a full set of tools and equipment. But they cover every part of the bike and have great drawings. Clymer and Haynes make DIY maintenance manuals for just about everything, including your bike. Try http://www.clymer.com/Book.aspx?bid=1233

Be sure to clean around the reservoir before opening it, and keep the cover on the reservoir when you step away, to keep dirt out of the system.

Refilling requires proper bleeding of the brakes lines, to remove any air bubbles. Make sure you use the same kind of brake fluid that was in there before.

  • Between step 4 and 6: Open the reservoir enough to allow air to enter and replace brake fluid as it leaves. I wasn't sure with the ABS, but this is exactly the same thing you'd do to drain/replace your clutch fluid.
    – Kendrick
    Commented Mar 9, 2011 at 15:38
  • @Kendrick: I removed the step-by-step, because I don't know about ABS systems, and I wanted to keep things pro.
    – Jay Bazuzi
    Commented Mar 9, 2011 at 16:58

In order to replace all of the brake fluid in an ABS system I always use a pneumatic fluid excavation tool.

Here is an image.

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Honestly, I use this regardless of ABS or not. It will create a vacuum at the caliper and the fluid will enter a waste container. If you use clear tubes you can see if it's pulling air out of the system as well. You continue to vacuum the system with the hand pump until you see fresh clear brake fluid which let's you know you have all of the old fluid out.

It's very effective and if you continue to replace the fluid as you pull it through air will not enter the brake system.


Here is the procedure for removing all of the brake fluid from your system and ensuring that the front and rear control circuits are properly bled.

  • I know this question is bike-specific but bleeding ABS lines can be a real chore because you have to activate the solenoids to open the valves; you may think you're don't because no more air is present when in reality there is some trapped in the ABS lines
    – Zaid
    Commented Dec 26, 2015 at 21:10

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