Originally Posted by
Spandex_fairy
I'm using Shimano/ mineral oil; looks like I'm good for some time then. The brakes were mushy from brand new. The service guy told me that's how it's supposed to feel. I didn't believe him so I took the bike home and flushed it myself (multiple times). It seems he was right because nothing changed. I'm using the short reach shimano 105 shifters that came on my 52cm bike. What a difference in pull stroke and force vs performance moto master cylinders, such as a brembo rcs19 or an Accosatto equivalent.
Maybe you should not -flush- the brakes, risking introducing air to the system. My tiagra hydro brakes was getting a little mushy after about one year. I only opened the top screw, put in the funnel with oil in it and and let out some air bubbles. Ive found pointing the front wheel down (like riding down a very steep hill) and gently tapping the brifter as you pump the lever easily lets the bubbles out. Airing out the system helped firm up the lever feel and it was a 10 min job for both brakes.