The Nissan Path

Thanks in advance for any help!!!

My brake fluid was a normal light amber color prior to having it changed. The fluid was in the vehicle for at least 1 year.

Had a flush done by my very trustworthy mechanic. I provided the fluid (new, sealed can of ATE Typ 200 Dot 4).

I picked the Pathy up and dropped off another vehicle that I was having inspected. Drove 2 miles to the barber shop for a haircut. Drove 2 miles back to settle up my bill 1 or 2 hours later. Decided to pop the hood and have a look at the brake fluid while waiting. Cap was on securely, but it was VERY dark!!! MUCH darker than before it was flushed. It appears black.

I don't have a before photo, and haven't taken any afters yet. Will post when I do. Before it was changed, it read 1% water on my (unknown accuracy/cheap) fluid tester. I will test it again and report back with that as well.

Brakes are functioning normally with good pedal feel. I have not done any panic or ABS stops or repeated stops from high speed, but the brakes feel quite good, definitely no worse than before.

What could have happened???

Corrosion in hard lines, degrading rubber lines, moisture???

Background on My Pathfinder:
I bought my '06 from its original owner 1 year ago. It was regularly maintained. There's a bit more rust on the underbody than would be usual in most climates, nothing crazy like a seaside environment or anything would cause, but the original owner lived in an area of PA that's gotten lots of snow (and therefore road salt) these last few winters. It's currently at 112k miles.

Thanks!!!

Any chance that the brake fluid you provided is just a darker color than what was in the system?

smj- Thanks, good point. I wish there was a chance of that. But, no, the ATE Typ 200 Dot 4 (what I used) is a light amber.

The same company used to sell a very popular fluid called Super Blue with the same specs that was, well, blue, lol. It had to be discontinued in the US because 'ATE Super Blue Racing DOT 4 brake fluid does not
comply with the applicable Federal Motor Vehicle Safety Standard for brake fluid, because that standard requires motor vehicle brake fluid to be colorless or amber in color.'

I remember Super Blue being very popular. Never used it, but apparently (and it makes sense) it made flushes very easy if you alternated with using the regular amber. You'd always know right when you got the old stuff out because of the sharp color difference between the two.