Hex bolt on 2003 T&C brake calipers

I tried to change my brakes on my 2003 Town and Country. I couldn't figure out what size hex bolt holds the calipers on. It seems to be an odd size between 1/4 -inch and 3/8 or 7 mm? If anybody knows what size I'd appreciate the info.

On my 2001 Grand Caravan it was a sixe #7 hex socket.