Where you've said push the piston back, this is a subject under debate.
There is an argument that the one spot in the "sealed system" where contaminates may enter is when the pads are replaced and the pistons forced back. The solution to this is to clamp off the flexible tube, open the bleed valve and push the pistons back. This then removes the excess oil - which is the oil most likely to have been subjected to extremes of heat.
Whether you agree or not, this is a method used by high end performance vehicle mechanics.
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I thought the van was blue, but now I'm told its Lilac
my pads are ok so just a clean and re grease with copper grease the pads are held in place with pins and have a r pin holding them in this will pull out with pliers and drift pin out from outside in with a drift or pad punch only take one out at a time so the piston can be pushed back 
clean pads if they have ant squeal shim put in right way up use copper grease on back and on pins 
put pads back in don't forget to pump pedal back up 
