You'll have to clarify for us a bit. Are you talking about the front strut assembly? You shouldn't need to leave the spring compressors on while installing in the car - the nut on top should hold everything together.
This is dangerous work to do if you are not sure what you're doing. You should be able to find the description/video of someone doing a front strut replacement somewhere online that shows how to accomplish this job. Volvo just uses the "Macpherson Strut" setup, which is very common in FWD cars all over the world so it's not hard to find folks discussing how to do this.
--
1998 V70 AWD->FWD Turbo 200k+
|