Slight digression but in the same vein.
Spurred on by this and other related threads, I've just ordered a brake (and clutch) fluid checker to check the moisture content in my systems.
Simple device you just dip it in the reservoir and note the reading. 1 or 2 percent moisture ok but 3 to 4 change the fluid.
However I have a question. Is the fluid in the reservoir indicative of the fluid in the system itself?
My system loses no fluid so in theory little if any reservoir fluid gets into the system, I haven't needed to top up the fluid in the 2 years and 8000 miles since the last change.
So I can understand how the reservoir fluid might absorb some moisture from the air gap and when opening the cap to check the fluid levels but how would moisture get into the main system down stream of the reservoir and therefore how does moisture get absorbed into the fluid?
I know it does absorb moisture and that it should be changed every 2 years but my brain is insisting I find out how and why.
Any thoughts?
