Brake fluid level changes two days after topping off.

I searched but could not find any occurrence under the Prius v section.

I was in San Diego when a dealer in the area found something that caught my eye and gave a really good price. So we went to see it and purchased it, drove it the 120 miles home, and parked it in the garage. Car now has 350 miles or so. Anyways, I noticed the brake fluid was practically at the minimum mark, so I topped it off to the maximum line. A day later it was I would say 3 mm higher than when I topped it off, and then another day later it was about 5 mm higher than when I topped off, now above the max line a good bit, so I siphon some out so it is just touching the max line again. The car basically sat there in the garage for two days, no driving.

Anyone have this occur to them or can suggest a possible reason? Thank you very much for looking, and take care.

 

Thank you so much for enlightening me on what is going on!!!

I opened the driver's door today and there was a sound that comes from the car. I went to look at the brake fluid level and it had gone down! Just opening the door activates this accumulator "pump". It looked like it was lower than this support line, but I didn't touch it this time. It was still above the minimum line...

I will try to search for the thread you write of to figure out what this new brake feature is about. (I've never seen it in other cars...)