crosman 102 valve removal help

Hi, i just got a 102 today that needs resealed, i was able to get the valve removed except for the very top, the compression chamber. Rick from precission pellet is sending me a replacement that has an oring grove cut in it. he told be i should be able to get it out of the pump tube with a dowl rod and hammer, it tried and all it did was destroy the dowl rod, didnt budge the compression chamber a one bit, anyone have experience removing these from the pump tube? Thanks, Dennis