Hi Robert,
I eventually decided that the leak was not so bad that I couldn't limp home, filling up with replacement LHM as I went. I bought 3L at Highland Motor Parts, Units 12-13, 21 henderson road, Inverness IV1 1SN for £4.26 each. That is the lowest price for a litre I have seen in a long time. I set out southbound and got to Drumochter before needing my first top up. That got me to just south of Pitlochry when I added the second. I got as far as Perth before adding the third. The red light came on about Dunblane and I ran out about 10 miles from home. I limped the remainder with manual steering.
When I looked at the hose in question before leaving (whilst trying to decide on my best tactic) I found that there was a tee in the pipe where the return from the steering rack joins the return from the regulator. There was no easy way to rig something up with no tools, materials or ramps.
When I got home I pulled the hose of the regulator to try to determine where the split had occurred. I cut back the moulded end on the hose and also cut back the protective plastic mesh to about 150mm back from the end. I bent the hose betwen my fingers in several places trying to find the split when the last 75mm broke off in my hand. Initially I thought, great, I've found the split and the hose has broken at exactly that point. Unfortunately, as John had forecast, the hose had become brittle over time and had split at a location completely unrelated to the leak. The split in the hose itself was about 15mm from the broken end and was easy to see once removed form the car. Bearing in mind what John had said about chasing the pipe further and further up towards the tank looking for a bit that was not so brittle I looked around for a suitable extension pipe and jointing mechanism. I found a string reinforced hose the correct internal diameter to go over the spigot on the regulator. However, when I tried to marry that up with the existing hose I found that their internal diameters were completely different. The end on the original hose must have been moulded into the larger size needed to get over the regulator outlet spigot.
I searched for a while and finally found a piece of steel pipe which matched the diameter of the exisitng pipe and a bit of copper microbore which matched the internal diameter of the extension hose. I hammered the copper pipe over the top of the steel pipe since their respective internal and external diameters matched perfectly. However, an air test still showed a minute leak between them. So, I ran a bead of solder around the joint between the two and sealed them for good. I inserted the pipe into the extension hose first and then pushed the other end into the existing hose taking a lot of care not to split the brittle material. Having succeeded at that I slipped the extension hose over th eregulator outlet and used mini Jubilee clips to tie the whole lot together.
The problem seems fixed for now. However, the risk will always be there that the existing hose will continue to become more brittle and will eventually fail again. I see that the Citroen part number for a replacement hose is 5270 L2 "Oil Back Harnes".
It is still available for c£80 here:
http://www.citroencarparts.net/5270L2/http://www.hcsale.com/shop/5270L2http://www.kfzteile-profis.de/page_1_3.php#oeformoFor the last one the page corersponding to the actual part is buried in their flash player and cannot be accessed directly through a URL. Therefore, just search in the box provided for the part number above.
I hope that helps anyone in a similar predicament.
Thanks for all your help and suggestions.
John,
I sympathise with your high pressure leaking woes. I've had to get the RAC home on two occasions with HP leaks. As you say, you first have to convince the controller on the phone that you know what you are talking about and the car cannot be repaired at the roadside. Otherwise you have to wait on the first guy turning up only to say, "<long sucking sound> There's nothing I can do with that, mate. You need a recovery", which takes another two hours to arrive.
As I'm no doubt you are aware the favourite location for the leaks which you describe are on the horizontal run of pipes along the crossmember between it and the fuel tank. That area collects dirt and never gets a chance to dry out. The pipes are also bent after the black paint protection is added. This casues the paint to fracture at the bends allowing moisture to penetrate and corrode the pipe. The pipe is highly stressed at the apex of the bend which accellerates the corrosion process (back to my metallurgy days at college). I have repaired these many times. They are actually easy to access once you drop the rear subframe. I cut the offending pipe(s) back to a point near the cill where there is a convenient straight section and splice in a new section from that point to the termination on the respective hydraulic component in that area. I replace the pipe using cupro-nickel so there's no danger of it happening again. I also coat the tubing nuts and splices in waxoyl because they are steel and will still rust otherwise and the cupronickel is too soft to withstand the twisting when the corrosion on the tubing nut binds to the pipe wall.
I hope you got home safely and can repair your leak.
cheers
noz