Hygroscopic – A Word Drivers Should Remember

Pronounced: /ˌhīgrəˈskäpik/

Yes, a word we don’t usually hear everyday that describes the tendency of a material to attract moisture. And one that I’ve forgotten, until lately when this cost me a four figure sum.


Why? Because clutch fluid is hygroscopic. And the result is this:


This is the thing behind your clutch pedal.
This is the thing behind your clutch pedal.


You see, metal corrodes when in contact with water. And it so happens that clutch fluid is a chemical that attracts moisture (water) from the air around and will become poor in quality as time goes by.


What you see above is the result of the corrosion. The spring in this clutch pump was broken into three. The resultant rust in the fluid is coarse and every single time you pump the pedal, you cause some abrasion with the rust particles in the fluid. Over time the seals will fail and there will be a pressure leak.
On the way to the trash bin.
On the way to the trash bin.


How apt, the workshop laid out my parts on the obituary page. End of life for these parts then.


As is the trend these days, car manufacturers do not sell small parts individually – the seals cannot be bought separately and so the whole top and bottom pump assembly was changed. Together with the dis-assembly then, the clutch was also changed to save labour on another occasion when the almost worn out clutch need to be replaced.


All in a four figure bill then. So what is the “alternative medicine”, that headline on the first newspaper page? Save your wallet by spending on the replacement of clutch fluid at least one a year. It costs about fifty bucks, will save you the inconvenience of the loss of use of the car, and a big replacement bill.


Before you say, aha!, I drive an automatic, no clutch fluid for me… Remember ‘hygroscopic”: the tendency of a material to attract moisture. It applies to brake fluids as well.


The next you know it, aha! I drive without brakes! That could altogether be more expensive than my broken clutch.


Stay safe on the roads folks!



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