GM-GMC: Brakes sticking, brake fluids, dot 4

Question
I had changed one caliper and that is the brake that sticks. I now have the line off and will replace that. Will this work and should I take back the caliper?-------------------------
Followup To
Question -
1991 Chevy c2500. Front left brake is sticking. I have changed the pads and was able to bleed the brake. Why is it sticking.
Answer -
DOT 3 and DOT 4 brake fluids are hydroscopic.  This means that they have an affinity for water.  These fluids will pull humidity out of the air through the brake hoses connected to the front calipers on your vehicle.

Result: Rust and corrosion inside the caliper.  This can cause the piston to stick and not retract when you take your foot off the brake.

Remedy: Go buy two rebuilt calipers from your local auto parts store.  They are inexpemsive and will restore proper braking to your vehicle.  Replace both calipers to prevent any uneven braking action that might cause the vehicle to swerve without warning.

Answer
You either have a rebuilt caliper that is working correctly and the other one is not building pressure, or the rebuilt caliper is defective.  It does not happen often that a rebuilt  caliper is bad, but it does happen.

I would take the rebuilt caliper back for a refund and then go buy two new rebuilt calipers from another store.  That will ensure that you eliminate the problem.  Make sure that both calipers have the same appearance, except for the differences for left and right side.