some dampers need to be check for fit and some times need to be hone it fit to get the right press ,you can get a damper tool at any parts store .that will do a good job of putting it on.BUY ONE. or see if you can rent one from auto zone ? if you must hit it use a rubber hammer or a pice of a 2by4 .a lot of the sfi dampers you do not want to hit it nothing looks nicer than hammer marks on a $300 damper