MK5 - or something?

[Couv]

I changed the Duro 90 O-Ring (#11 in rsinglers schematic) to a Duro 70

I would not use a duro 70 in that application. The pressure differential is way too high. Please try a new, known good duro 85-90 for the piston stem o-ring.

 

[qwertz]

Thanks once more for the input. Your explanations are the reason why I went with a 90 in the first place.
Maybe I ****** up sth. else and fixed it with the reassembly. I will change to 90 once more and give it a try. Cheers!