Been getting random CHECK BRAKE SYSTEM warning for past two months. Always seemed to be just at bottom of a hill. I would hit the OK button and ignore it. Went out to get gas today, got it again at bottom of same hill. Dismissed it. Then noticed an idiot light on instrument panel also crying about brakes.
Stopped at auto parts store that I was about to pass, popped hood, checked brake fluid level. Right in the sweet spot, half way between MAX -- MIN, an inch to go either way. Bought some fluid, added up to MAX line, wiggled wires attached to master cylinder, closed hood. Started truck, did a few hard brakes in the parking lot. Problems seems to be solved. We will see.
View attachment 479593