[shorod]

Since you mention you geared down, I'm assuming this is a manual transmission vehicle. And, since you mention it was a friend's car, I'm further assuming you are not real familiar with this car.

Based on the two above assumptions, is there a chance that you stalled the engine in the process and that's why the brakes did not work as you were expecting? Was the steering also harder than usual, contributing to what you think might have been slipping? What about the weather or the road surface leads you to think a wheel might have slipped?

-Rod