How did brake fluid reservoir filled up with water?

[Bonifatich]

I've been away for 2 months (May-June), parked the car on the curb and when I returned brakes felt like I was driving on eggs. Mechanic told me my brake fluid was water, not brake fluid. He has no idea how did that happen, nor I do.

The car is C200K, 2001 production. I bought it 3 years ago and never changed brake fluid nor had any problems with it.

The car was driving fine until after I left it for that period.

My major concern is how did it get there and does it mean it can get there again and should I expect consequences else where?

Regards

 

[Howard]

Anyone borrow it while you were away and might have topped up the wrong reservoir with water on a hot day ?

 

[Sp!ke]

Brake fluid is hydroscopic. If you've never changed it its water content would increase as it absorbed more moisture from the air.

The higher the water content the lower the boiling point.

You should change the brake fluid every 24 months.

 

[lxi]

Brake fluid is hydroscopic. If you've never changed it its water content would increase as it absorbed more moisture from the air.

.

You are absolutely right, but I've always wondered how the fluid comes sufficiently in contact with the air to absorb the moisture !

 

[panason1c]

The cap of the brake fluid reservoir is 'vented', thats how moisture laden air comes into contact with the fluid.

 

[Bonifatich]

The car wasn't borrowed definitely. Mechanic did the job perfectly regarding replacing it with brake fluid, no problems now.

However, brake fluid being hydroscopic + reservoir being 'vented' and brake fluid has not been changed in at least 2 years perhaps added to the problem.

Thank you for your comments.

 

[pingping]

never came across this before with any car i have driven ,quite strange.

 

[kth286]

badly maintained braking systems can have rust in their delicate internals, which is not good for seals and their capacity to maintain an efficient working system.

You are only likely to know about it in an emergency braking action.