Rear Coilover top mount vertical movement??

Hi All,

Im a newbie and have had a 1983 cabrio for about 8 months, the shocks on the front required replacement and i plumped for replaing all with some coilovers…

however i have fitted the rears with the rubber beneath the rear suspension mounting plate and the rubber on the top with the metal "cup" and top securing nut as per the coilover fitting guide but if i put any weight in the car the whole rubber moves up about an inch and i cannot see how the shock is doing anything at all!?
The car is bouncing on the spring only?

please any help would be greatly apprieciated

thanks scott