Daft? Clutch Slave cylinder question.

Hi,
I'm in the process of converting from 5 speed to 6 speed..
All going well so far.

The clutch slave cylinder was gunked up and leaking a bit so I've changed for a new one.
The new one (and the old one now that I've taken it off and checked) both have an internal spring that forces the piston forward.

I can't quite figure this out... I'd have thought that this would apply constant pressure and contact of the release bearing with the pressure plate springs.
I always thought that the release bearing had to sit slightly away from the pressure plate when not in use (otherwise it would quickly trash it)

I've not seen a return spring on any of the Alfa gearboxes, so thought I'd ask this daft question in the hope that someone might be able to shed light on it.

Cheers
Andrew

Pull type cylinder?

Hi,
I've a number of scrap slave cylinders and each one has an internal spring pushing the piston forward.
The original 164 (push type pressure plate) had a spring and that's what I was using until I've come to change it and query the principle.
In theory, the pull type pressure plate work back to front, so the internal spring would still have the release bearing pressing onto the pressure plate.

Have I missed something basic?
A

If its a lightweight spring, maybe its there to keep a very slight pressure against the bearing and stopping the piston pushing fluid back, similar in principle to those anti knock back things fitted on some hydraulic brake systems?