ive put them under a few cars74 nova 55 chevy and a few others. all i ever did if i remember right is have a floor jack under my a arm and went to jacking up. i never had to compress any of them. though on the nova i did have to get the spring in place with a hammer.(bfh). do you have the right springs for your car?i had the cars up high enough where i could push down on the arm far enough to get the spring to start in postion then jacked it on up. i did once have to have a friend sit on a fender cause the car wanted to go up before i got the a arm in place.