Mitsubishi 1993 3000GT Technical Information Manual page 59

A 4" single type clutch booster is used to reduce the
force to depress the pedal. The structural operation
Push rod
Booster return spring
Diaphragm
Booster piston
/
Negative pressure chamber
of the clutch booster is basically the same as with the
brake booster.
Valve plunger
Poppet
Operating rod
Valve plunger stopper key
'Reaction disc
Air chamber
Filter
08F0007