[DeTomaso] clutch master cylinder air

[LEVITT1946 at aol.com]

Dear Friends,
 
My saga continues on air in the clutch hydraulic system..
 
I have found slight leakage of brake fluid below the reservoir of the  
clutch master . Below the  reservoir is a nut and a flat washer .That  
nut/washer is then tightened and lies between the reservoir and the master . 
 
My questions is ...should there be some kind of a gasket to prevent leaking 
 and a tight fit? Is something missing ?  Or do I just tighten the hell out 
 of that nut and hope it makes a tight air tight seal? 
 
 
Regards,
Robert 
 
 
ps....if anyone has pics of their master it would be greatly appreciated  .