Volvo Repair: 1993 Volvo 960 gas gauge, 1993 volvo 960, volvo 960

Question
My gas gauge works intermittently--usually reading empty. About 10% percent of the time it will read a proper level. I don't know how to get to the back of the gauge to see if it is loose.Any thoughts?  

Answer
it would be difficult for me to explain how to remove the cluster.I ould check a local parts store for a repair manual or try the local dealer if possible for a prit out of the instructions which will also have photos to help.it is probably the guage that is bad though.