how can i fix my saxo vtr axel?

just fitted a axel to my saxo vtr 2000 pas side back sitting at right height driver side back is sitting very low nely tuching the mud flap when jack up and let down againe the car sits at the right height but when you push up and down a few times it sit low on driver side back is there a spring in the axel some were which mite have broke or size up