Well - all was too god to be true..... Took her over to the Bunker Bash the other weekend and, when we were leaving after the show finished, the same damned brake circuit seized on again. To say I'm not impressed with the work done by a certain firm now is an understatement!!

So she is stuck over at the Bunker for now,
Anyways - in the interests of getting a "fixed once and for all" solution Lee has kindly offered the help me strip the whole damned brake system down and rebuild it. On Wednesaday we took of each flexi-hoe in turn and put a pressure tester on the system to see what we were getting. The EMER says we should have 2160 psi at each wheel station with fully charged air packs. What we actually had were:
Rears - 1200 psi on both - O/S pressure releases slowly (this wheel is not on the circuit that was seizing on)
Centres - 1500 psi on both
Fronts - 1100 psi N/S side, 1000 psi on the O/S side.
As Lee says- the fronts low reading might be due to air in the system from doing the rears and centres. All but one (O/S Rear) of the flexi-hose unions had never been removed in years and the front two had to have the leading pair of shock absorbers & bump-stop released from their top mounta to access the hull points for the flexi hose.
Both front flexi-hoses were rotten and tore apart during removal and the rigid pipe on the front O/S calliper burst during testing - a lucky escape there!!! Sprayed Lee with fluid though...
Right now the plan is to rebuild the hydraulic circuit(s) by replacing all six flexi-hoses, both rigid lines on the front wheels, all the calliper seals, pads and the master cylinders (got to replace the whole cylinder as seals kits aren't available). May need to get the brake discs skimmed as well - will know better once the road wheels are off.
We also need to remove and check both the air-packs and the sensing tank as it's venting compressed air a LOT faster than the book says - could be a crudded up auto-drain down valve on the sensing tank?? Sitting in the cab as soon as the engine is turned off escaping air can be heard very audibly and the air pressure gauge drops rapidly. Build up of air pressure after restarting is also very slow.
Then the plan is to flush the entire system through with fresh fluid - what came out today was discoloured, stank, and varied in viscosity, colour and smell at all 6 wheel stations!!! I popped down to see that nice Mr Banister on Friday to pick up the hoses, pads and various seals needed for the calipers plus two new master cylinders ans no seal kits are available - and parted with about £890
Now the odd-balls that occured that day!!!
Sitting in the cab with air up I decided to try the main wiper motor again as it's been working only intermittently and a light rain had started.
Soon as I turned the knob to "Run" - I got squirted by a jet of water mixed with oil from the hole the manual control lever goes though. How the hell did that get full of water??? Wiper worked OK though!
And finally - to add the icing to the cake - the oil pressure has started doing weird things. Starting from cold it's constant at around 25 - 28 psi but as she warms up the idle pressure drops down to 10 psi -ish that slowly raises to about 15 psi as engine revs increase. I'm assuming an urgent oil filter wash or change plus a of engine oil seem to be the next jobs after the brakes......
Some photo's of the work in progress (not too good, they were taken on a camera phone):

