hi sages- need some advice on a rare volvo of a friend. it is a 95 850 wagon fwd 5cyl. left rear caliper seems to have stuck or slow pistons. looks pretty old. want to replace it. mystery is 3 parts stores say there are two different calipers for that model. one has 11mm mounting bolts(2) and the other has 10mm mounting bolts. checked the size on this one with sockets and the mounting bolt heads are 13mm on both sides. wtf. wondering if the above stated sizes refer to the threads not the heads or if there was a midyear change that the vendors dont know. what think you. know that bolts dont usually size like this, but have seen it in rare cases, in cars. thanks tons oldduke