How can I install PU jacks without a rotary stick

Now that I have started to remove a little reperture I have encountered a problem and I find no solution there. I wanted to replace the socket of the upper engine bearing and get the old one out quite easily. Then one half of the PU sockets inside and the second one does not want to go in. I also tried with a vice but this stupid part always misunderstood itself. Now the part is still extended and now I have two questions: 1. Can I use drive the car even though the upper support is still missing? before it was also very loose… 2. How can I get the socket still in there? Does it go with cold (pack over night into the freezer? Thanks for the help….