sticky clutch

[zetor_baz]

g'day
I am new to the forum, i have a problem with my ND9-031 forklift,
the clutch seems to be sticky but not all every time?
most of the time I can feel and ride the friction point out and take off smoothly, but sometimes my foot can be off the pedal completely before it lunges forward?
I have changed the clutch master cylinder with a genuine part from zetor australia so I know it not that?
any help would be apriciated

baz

 

[Renze]

grease the pivot arm of the clutch throwout bearing. or use penetrating oil first, then grease when it is smooth again.