I HAVE A 179 FITTED IN MY FC, THE REAR MAIN SEAL LEAKS NON STOP , IVE REPLACED THE SOFT SEAL 3 OR 4 TIMES  TOP AND BOTTOM. THIS WORKS FINE FOR A WHILE THEN THE LEAK RETURNS, . ANY IDEAS ON HOW TO FIX THIS PROBLEM ONCE AND FOR ALL. CAN A LATER TYPE OIL SEAL BE FITTED WITH MODIFICATION TO THE JURNALS? IF SO WHAT IS INVOLVED.

all brake tube must be seamless bundi tube   i think its 1/4 inch from the master cyl. to booster  and 1/8 for all other tubes   the ends must be double flared

ive used the red lens dye in a bottle,  its hard to get an even coat  and it fades and frosts over after about 6 months in the sun, ive only put it on the outside of the lens  it may work work better on the inside    a spray can sounds ok.