Changing the pipework was not that difficult (although a bit of a squeeze for Anrew, who insisted in inserting himself into the bowels around the propshaft and torque reaction bracketry and thus had tools passed to a hand which appeared from time-to-time through the access door under the desk). Thereafter we filled the coolant, fired it up and air pressure built back to normal levels.
But not functionality. The pneumatic diagram for the Sentinel system (which I had in any event forgotten to bring with me!) is not drawn to the current British standard and for one whose head is best set for that, interpretting the old diagrams can be tricky. Sometimes they are drawn with everything "at rest", sometimes they are drawn with the system set in a particular condition. Should you also be unfortunate enough to have a diagram where the state it has been drawn in is clarified only in the manual's text and I may I think be excused for having piped the replacement poppet valve the wrong way. But Andrew didn't seem to think so, and tempers got a little frayed. They became even more frayed when having reversed the valve from normally open to normally closed (it is a mark of the antipathy between pneumatics engineers and electricity experts that the term 'normally open' means the complete opposite when applied to a relay rather than a valve) it made no difference whatsoever.
Cracking various lines up the system, Andrew concluded that the culprit was in fact a 'double acting air operated pilot valve' farther up the system since this dictates whether the air supply is routed to clutch "out"or gearchange, and since we have gearchange, he deduces, the valve must be stuck on that position (and there is not, he determine, air on the pilot to hold it there). So it is my job to source a replacement valve. I do so hope he is right, but like I said, the Sentinel pneumatic systems are a law unto themselves and sometimes I think it would be easier to rip the whole lot out and start all over again...
We had already scratched Saturday as a work day as Andrew had to be away at the girl friend's and Steph and I had our daughter and her partner calling. But in the event even Sunday was out as we went to Kettering to visit an old lady who is a guest of the NHS at Kettering District Hospital. I cannot recommend Kettering as a holiday destination. The hospital is depressing (they still have a plaque in the entrance celebrating the refurbishment of the area in 1991 - I think in 2012 I would no longer want to advertise it), the lady managing the WRVS buffet made it clear that I was a complete moron to ask for a cup of tea rather than realise I should make it myself from the materials in front of me, finding our way back to our car took us nearly a quarter of an hour (dead ends and locked doors) and from what we could find, the entire town has only one petrol station.
Anyway, apologies to my readers from the DVLR that we did not make it back today to finish "Pluto" off - it is now planned for next Saturday which is the first weekend of the month. I wonder if it will all go to plan?