waxy substance in brake fluid master

Over a period of time brake lines will accumulate condensation. This is one of the main reasons we want to change the fluid regularly. Too much condensation will cause undue wear on the internal parts of the brake system. Also if the brake fluid ever got very hot from heavy use it could cause thermal breakdown and again cause undue wear. Most people do not realize that condensation will build up on a closed system such as brakes. But it definitely does happen.

If the brake fluid was original from 2004 it is very possible this flaky, waxy substance could be due to breakdown of the fluid and resulting wear. When you completed the fluid change and bled the lines did you notice any substance coming out with the old fluid? You might want to check the brake cylinders at each wheel to see if they are clear. Those four piston calipers need attention. Or are they two piston??? Gosh, I forget what they were in 2004. If have slept since then. If it is contained to the master cylinder possibly you got off light and can just clean the master cylinder float and be done with it.

 

This is caused by moisture in the brake fluid. My suspicion is the fluid has not been changed at the intervals suggested by the manufacturer. This will be throughout the entire system and can be a concern particularly when it migrates into the ABS components.

 

It is easy enough to change all the fluid in the master reservoir every year and then do the whole system every 4 years. It will stay as new. I do this to all cars every Jan or Feb. I also do the power steering fluid reservoir every 2 years.

aehaas

 

Interesting idea.

I suppose, theoretically, if you changed the master cylinder fluid at a specific interval, say, once a month, that after several months you would approach a total system change, assuming the fluid would gradually equilibrate through out the system.