87 300td wagon suspension issues

[Tdwagonin']

Hey, I have a old car feel for my benz. When i hit a bump the car doesn't stop bouncing. People say to change the shocks but they are not regular shocks they have that hose coming out of the top of it.

Some people said to change a part in the shocks but I am new at this and have no idea where to start. I think it is just the rear shocks.

Thanks for the help