Since you are replacing them,
what with?
Not having worked on clansman I'm betting they are completely the wrong length / tuned frequency
The old aerial will probably receive FM radio, but finding out how long they are and tuning them to the correct division of FM would make them work better.
Trying the transmit 27 MHz on clansman aerials has a good chance of damaging your CB, it's even more important to have a correct tuned Aerial for transmission. Get it wrong and the reflected power would bounce back and kill your output circuits.