Five days ago, I noticed a small leak accumulating around my right rear drive wheel. The color is dark brown with foam on the top. The leak has since grown bigger.

Here is the latest picture:

http://bit.ly/sj960p

Does anyone have an idea what it is? I'm thinking hydraulic fluid, but I'm not sure. I'm also thinking a recent cold snap brought about the leak, if you recall the Challenger disaster, o rings, and frost, decades ago.

The bus is 15 years old with 130K miles. Prior to my buying it in September, it spent over three years stored in a barn north of San Francisco.

My concern is that it is not drive able and that I will need to have it towed to a bus garage.

I will appreciate any insights.

Oh, and Merry Christmas everyone.