Guys I have 3 bottles of the AP formula 5.1 brake fluid that's been sitting in my closet for 5 years or so. Would it still be good to use or should I pitch it and get new ones? Also is this type good for my stock sport brakes? I just upgraded my setup so I wanted a full flush as well. Also it should be noted I dont race my car, its a daily driver in blizzard and sunny conditions. Thanks!

 

The issue generally is that brake is hygroscopic and will absorb moisture, given the chance. If the bottles are unopened, that is less of an issue, but plastic bottles are never really 100% sealed. You say it's 5.1 which is formulated to absorb less water by nature, although 5 years is a long time.

If it were 1 year or less, I'd say go for it, but being 5 years old, I'd say absolutely not. Brakes are the last thing you want failing while you're driving, and fluid is only like $30.