fixing brake caliper

[timbowuff]

my back brakes were seized up, so i took the caliper off the brake(fluid line still connected). i was able to push them in again and now both of the cylinder sort of things(what do you call them?) seem to be compressed by the same amount but they dont spring back much when released.... anyways what should i do? my first time looking at brake calipers..... should i drain the fluid and put new fluid in? would the seal on the brake cylinder things be broken or stuck somewhat? also i could always swap with the front brakes but i want to figure out the back brakes and learn this stuff....
thanks a lot!!!!

 

[Doc Sprocket]

both of the cylinder sort of things(what do you call them?

Pistons.

but they dont spring back much when released....

They shouldn't. Don't worry about that.

Now that both pistons are retracted, see if pushing the pedal causes them to come out again. A word of caution- Loosely place the caliper back over the rotor, or place a steel plate between the pads before doing this. If the pistons overextend, you'll blow the seals out. Do note that pad movement will be very minimal. It should take several pumps of the pedal to bring them back into contact with the rotor again.

 

[timbowuff]

yes pushing the pedal causes them to come out equally.... the pads are out as of now.... how do i know if the pistons overextend or not??? will the pads push the pistons back in when the pedal is released???? how do i know if i need to put brake fluid in or whatever? thanks a lot...(as u probably guessed i know nothing about this, but want to learn