Brake System Failing
So I did some heavy mudding today and after leaving the trails and driving around 10-15 miles my brakes started working on and off. If I pump them I get pressure back, but then the petal will go back to the floor next time I press them to stop. I couldn't find a leak in the front or the rear. I checked my master cylinder and the front was fine, but the rear only had about 10% left in it. What is weird though is I have driven without rear brakes before and know the difference between just the rear failing and my entire system acting up. Does anyone know what this could be? I couldn't figure it out at all and ended up having to park it until tomorrow morning in a friends backyard about 5 miles away from me.