i had this problem and i ended up cutting the danm things off as no matter what i did they wouldn't budge. you do mean the cap on the top mount?
 
when i did my suspension i ended up cutting them off (well with a screw driver) as i was trying to try them out but ended up punching a hole in them.... the engine bay looks much better without them too
 
They are a twat, if u want to refit them and you need to remove them without breaking them take the shocker off at the hub and brake flexi and abs wire, undo the 3 bolts on the top and then pull the shocker from inside the wheel arch but tilt it to one side and give it a damn good pull, should come out then leave the black plastic cover still in, the it just pops off.
 
Managed to do it in the end, got one off with screwdriver and cut off the other. Thanks for ur help :thumbup: I think im goin to leave them off now, looks good imo