Before installing the new pads will check how the two parts are moving carriage with respect to each other. They have to move, even with a noticeable resistance. Move the item in one extreme situation after the other. If you do not get stuck anywhere and dust covers moving parts intact, you can put the new pads.
If the caliper moves very tight or not moving at all, it is better to analyze, clean and lubricate.
To do this, remove the screw on the support that holds the guide. For the convenience of loosening put caliper into place and capitalize on one screw.
Now you can disconnect the caliper.
With the fixed portion near the guide bushing remove dust covers. On the one hand, it can only be removed after pulling out of the guide, so do not pull the power - you can break them.
The guide is rusted and not moving at all. We'll have to beat her. But by itself it can not knock, it can be damaged. Take the bolt, about the same that it was holding (but not the same! So you can damage the hat), insert the inside so that the hat lying on the face of the bolt through the rail and begin to beat her with a hammer.
Bush moved, now part smazhem appeared and zabem her back. Then again. After the second time the interior must be smeared, stroke bush to relieve, now it can knock out to the end. Why not immediately clear? Why split hairs too much? Yes, but if you remove the caliper and conveniently located. And almost shed (because the caliper brake hose on the short) is more convenient to develop first a little bush. And so it was done. And again, you can wear a support on his seat, tighten the lower mounting screw and without unnecessary movements dislodge the plug.