Today I noticed my rear driver side tire had black fluid spattered across it. I cleaned it off and drove it for a little while, then parked again and there was more black stuff. I don't know alot about cars so please help. Thank you.
64 Chevelle SS.

Sounds like you have a leaky wheel cylinder. Be sure to check the fluid level in the master cylinder and keep it full.

I'll second that! Swap it out ASAP as it will most likely start to grab and cause a wheel lock up when you least need one.

Lita
Like Bryan said brake fluid or could be a axle seal leaking.Diff lube has a strong smell to it.If its brake fluid don't get it on the paint,Because it eats paint!Either one the brake shoes are most likely soaked.
Have it checked out.

-Kid