how do you replace the rear dust seals on the 200 callipers

had a look on the weekend and both my piston seals on my callipers are worn and split how can i replace them
without taking the calipers off the car
 
had a look on the weekend and both my piston seals on my callipers are worn and split how can i replace them
without taking the calipers off the car

Just been stripping mine and unfortunately you have to wind the piston right out as one end of the seal sits within a internal recess within the bore of the calliper. Sorry mate not a quick job!