I was checking the fluids this afternoon, and I took the lid off the master cylinder reservoir, and had a good look inside.... Most of the fluid was a yellowish colour, but there seemed to be several spots of clouded fluid, but there was also something sitting on the bottom of the reservoir, almost fungae/moss like in appearance, it doesn't look too good, but its not sludgy or anything like that, and the fluid was only changed about 12 months ago. Any ideas what the go is here, or am I worrying over nothing? The fluid I am using is the Castrol Response from memory, the one in the silver bottle.
I've often noticed that - what I've done is syphon all the old fluid out and mop up all remaining fluid in the reservoir. Then I fill the reservoir with new brake fluid which is a different colour to the previous one. This way when I bleed each wheel I can tell when the new fluid is coming thru and all the old stuff has been flushed out. I've also been concerned with what appears to be droplets of condensation on the rubber seal under the cap - I always wipe these away as they are probably water which when mixed with brake fluid maybe can lead to the cloudy fungusy stuff you mention.
