I changed my rear tire when i had that flat and the rear right tire on the inside of the wheel is caked in brake fluid. I know its brake fluid because i keep having to refill my brake fluid every few days. What gaskets or seals would i have to replace?

 

You could fix this two ways, both are cheap.

One is a rear brake cylinder seal kit, that basically replaces the rubber parts.

The other is simply replace that wheel cylinder. Couldn't be more than a $20 part.

You'll need to bleed that wheel.

 

A leaky wheel cylinder is most likely but first make sure the bleeder and all the connections are tight. You might get lucky and find something loose. Also look at the brake lines for any leaks.

 

If it's been leaking for some time there may be a build up of fluid sludge on the brake shoes. On mine it was completely caked, so I changed the shoes as well as the cylinder. Later I was told I could have cleaned up the shoes and lightly burned off the excess fluid with a propane torch, but that was after the fact.