i have a 09 clubman, I was going to change my brake pads when I loosened the last bolt on the bottom of the caliper brake fluid leaked all over the floor. what happened? I have the type of calipers that pull off from the side.

 

Picture of which bolt you loosened...
Sounds like you loosened a bolt in a "bung" aka an opening in it that a bleed valve could be inserted if it was mounted on the opposite side...the bleed valves are usually on top... But the same caliper can sometimes be used left or right....just reverse the "bung" and the bleed and the hoses for mounting....
If this IS the case...bleed...
If not...sounds like you need a rebuilt or new caliper...
Just a guess...I have a gen1, and are not familiar with the gen2 ones....

 

this was one of the bolts to take off the caliper. on a normal caliper I've always had to undo 2 bolts this has 4. normally you use a prybar to pull it off this one pulls off from the side. I've never seen one like it l was taken by surprise when I saw it.