[joemust]

I recently had my brake fluid reservoir "topped off". It was on the "Min" line. I seem to have to do this about every six months. Is this normal? If not, what could be the cause and is it complicated/expensive to fix?

[heavy metal]

How much was missing?It is normal for some fluid to evaporate over time.I suggest to check the system for leaks and go from there.If the brakes are fine and there are no leaks,then it was just evaporation.

[joemust]

I would say it goes down about a half an inch every 6 to 8 months

[heavy metal]

Sounds like just evaporation,it is normal.Also as the brake pads wear the fluid level drops,which is normal too.

[EagleAutosports]

It's most likely brake pad wear. When they wear down, it takes more fluid to engage the pads, meaning the system draws more fluid into the lines. If there's no leaks, all that fluid is most likely still in the system so keep this in mind the next time the brakes are serviced. I've seen this scenario several times:

Brake fluid level drops and the owner "tops off" the reservoir. Eventually they get the pads and shoes replaced, and the first time they hit the road afterwards they get a huge mess under the hood, the brake fluid reservoir overflows and they don't know why.