I ran into this on my 960. Whether it applies to the 850 I am not sure, but seems likely. Apparently the squeaking is a factory problem they fixed by including a shim on the pads. It is attached to the Volvo pads, but if theay are not volvo pads, the shim may not be there. To remove the squaling on mine, i had grooves cut across the width of the pads, and the leading edge ground down a bit. The fellow who did it is a 25 year volvo mechanic, who has eleven bricks. In any event, it worked, and may on yours too.