I bought a used Elantra, and now on cold mornings, the gas struts will
not hold up the hatchback. I bought a pair from a dealer, and he mumbled
quickly you remove the circlip on the old one to get them off, and the
other end just clips on. I hope so, the mounting bolts can only be turned
with a ring spanner. Also the new ones appear to be compressed.
So after you get the new ones in, you must do something to release
it so it can extend.
(and of course you need to support the hatchback when the old struts
come off)