I had a similar problem when renewing my wires. They only way i got them off was after i removed the top heatsink. I was removing this anyway to fit the speedo to my 12th scale so it wasnt a problem for me. BUT I WOULDNT ADVISE ANYONE TRY THIS as it will be near impossible to get it back on properly. I dont know what kind of nuclear powered soldering iron gm uses but mine woudlt touch it.