So i went to the lake this last weekend and when i got home i was backing the boat in to the garage and i backed it up like 10 ft, had to go move something and walking past the hitch their is a black cap on the front of the trailer, i think under it is cylinder for the brake fluid or something. But it was leaking oil? Could this possibly be overflow or do i need to get that replaced? Im guessing i can still tow with it, ill just have weak trailer brakes. Any help is appreciated!