Jonathan,
Clarification: There is no return spring on these trucks for the release fork. The bearing is in constant contact with the diaphragm spring tips, it is known as preload. The preload comes from the spring inside the slave cylinder applying a force to the fork to the bearing to the spring tips.
I do not know of any current hydraulic release system in the US market that has a return spring system. Some may take this as a trivia challange, and find some 1960's vintage app that does, I'm reffering to our popular current fleet of domestic and import vehicles, cars and pickup's.
Also, earlier you quoted me showing that I stated many here have used some technique to spread the frame rails. I am not suggesting that, we use the technique that I mentioned, we have never spread the rails.
Thanks, so it looks like my logic is flawed, since the play would be taken up as wear occurred. Never had a truck with a Hydraulic Clutch, and the last car I did a clutch on was a Golf II, which had a 'self-adjusting' cable. Selling the Volvo V-40 before I have to get into it.
Thanks to all... JK