Truck Repair: spring shackel wont take grease, frame spring, shackel

Question
I am unable to get a 2002 class 8 Freightliner's drivers side rear spring shackel to take grease. I have removed the zerk fitting and cleaned out the center bushing and injected BP solvent/lube. New zerk installed and I still can't get grease to flush out ends. Is heat my next step? Thanks!

Answer
Well technically you are suppose to get the weight off of the front end to grease them.They might be worn out.Does it make a popping sound when turning??If so,its worn out.You can change them with a bottle jack between the frame & spring nearest the front axle.You can buy a complete assembly.