The lube goes on between the shim and the piston when I do the job. Let it get a little crusty before you reassemble...Clean up every surface that the pads ride on. That means running a wire brush inside both ends of the caliper where the ends of the pads ride. Clean up and never seize the pins. Never seize the inside end surfaces of the calipers too. I chased the squeal for weeks until I went to the trouble of cleaning everything. Only took once to teach me, and I never had the problem again.