Originally Posted by
Wobba
You can unseize a caliper. You need to jack up car, wheel off, pads out, sliding pins off (if front calipers), red grease em (normal grease eats the little rubber gaiters)...get the pistons working back and forth. I've used g-clamps before to wind the fronts back a bit.
The rears have a slot in the piston. You can slot a flat head screwdriver in the slots and turn the pistons to wind it in or out. Do this till its nice and freed up.
You can do tracking yourself too, but it wont be that accurate.
If a good drive does not help the emissions, a new lambda and coolant temperature sensor might help.