I drive a 1988 XJS have owned it sense 1990 been trouble free for many year
but this year have had AC problem and brakes problem
Parking brake not working does any one know what the matter with it everything is new at rear

 

I have the same problem. Have not figured it out yet. I checked the brake fluid and disconnected the battery but still not working.

 

Most likely whoever did your breaks did not adjust your parking break, so its still set for the old worn out setup. It has nothing to do with fluid or battery.