Valmet 8000 clutch adjustment help!

[arbwork]

I have on going problem with clutch pedal movement any help appreciated, I can see 2 adjustable items as pictured and have bled the system, I have pedal not returning back intermittently and working ok at times, gasp  

[Canal Navvy]

I've come across similar symptoms on a 7 1/2 horse box lorry. Part way down the pedal stroke

a spring went over centre and gave assistance, it relied on the clutch springs to push it back overcentre on the return. A slightly dodgy master cylinder let the fluid go early and the pedal would stay down.

[arbwork]

similar system I think, some rod spring over center thingy , master cylinder is a little wet and is the next thing to replace as options are getting near to having to split the tractor, clutch and thrust bearing were replaced fairly recently in tractor hours but not in real time! it has not lost fluid from reservoir so I had thought ok but..... looks wet from photo  

[Canal Navvy]

My victim was leaking back into the reservoir, so not any external signs. Most of the time the clutch was good, just occasionally the pedal stayed on the floor. It drove the owner half mad