The chain doubtless broke at the pin you reused. The pins on those chains are not intended to be pressed out and back in. The ends are peened over and when you press them out the peened-over parts get sheared off and there is only friction remaining to hold the pins in. As you have found that is not enough. Use the master link as it is intended. You should be able to remove the proper half link (outer plates) at the broken end and close the chain back up with the master link. It should then last its normal service life.