After all the fun of getting XPO running again, finding the hydraulic leaks, and changing the steering rack, the leaks have not stopped. While the flow of green blood has definitely been stemmed, all is not well with the fluid return path. However, all the leaks seem to be at the front of the car, and limited to just one area. Will a hydraulic octopus change resolve the issues?
Finding the Leak
After the previous episode, I changed the steering rack to a refurbished version, hoping to stop all of the low-pressure leaks. While the replacement rack, with new pinion seals, has made a notable difference in fluid loss, I’m still enjoying some green puddles from XPO. Fortunately, the puddles are landing in the drip tray, and I’ve noticed they seem to increase when the suspension rises and falls. This is a reasonably good sign I haven’t made things worse with the steering rack.
When hydraulic pressure is added to a component, some pressure will inevitably be lost as fluid finds it way past worn seals. Citroen recognised this so most components have a leak back path. The low-pressure fluid trickles out of the many components, including the suspension struts, brake valve, steering valve and height correctors. At the front of the car, these small rubber pipes send the fluid back to a joining block and then back to the fluid reservoir. These leak-back pipes and connection blocks are collectively nicknamed the ‘octopus’.
While I visually checked over the octopus (long ago) before putting the engine in, clearly, there is a break in a pipe which I did not see. There are so many pipes in this area, that are hard to see into, the leak could be coming from anyone. Rather than bodge a fix, I might as well change the whole set of pipes. I’ve done this before, on my back in a car park, how hard can it be on a scissor lift?
Understanding The Octopus
Depending on the spec of the vehicle (mostly with or without ABS) there may be one or two octopi’. On XPO there are two octopi, a main one (the large octopus) and a secondary set of pipe (small octopus). I’m hedging my bets and only changing one octopus.
The lovely people at Chevronics have had the octopus for the Citroen BX remanufactured. When it arrives, the remanufactured hydraulic octopus looks like the picture above. Ignoring the white sticks, the octopus is a very good match for the original and not brittle like the one on XPO. All I have to do is perfectly swap over each of the original pipes for this new rubber spaghetti.
Fortunatley, I dont need to work out the piping arrangement as there is a fantastic guide already available at;
http://www.mars.dti.ne.jp/~ynar/bxorg_archives/m15/m15e.html
The pages show the overall layout of the octopus, where each pipe connects, and more importantly, the order of the pipes at the reserviour. I confess that I’ve tried to write a more detailed version, but other than improving the resolution of the pictures, the old Citroen.org pages are fantastic.
The pages even look at the structure of the inside of the middle connection blocks of the octopus. Something that can be very useful when trying to understand why the connections are made the way they are.
Changing the hydraulic octopus.
I’ve found it hard to describe in words some of the fiddly parts of the octopus change. There are many steps better suited to a video and a not still images and some text. What I’ll present here is simply some of the steps i take to the octopus change, and a few tips. It is not meant as a complete guide.
Marking up the pipes.
The pipes that run back to the reservoir have to travel through a piece of plastic sheath as they come up the back of the engine. This stops the pipes from slipping into places they should not be. Once they have been fed through the sheath, I find it impossible to tell which one is which.
So before starting, I put masking tape on the ends of the pipe and label them as per the Citroen.org guide. Covering the ends also stops the pipes from getting full of dirt when fed up through the sheath.
Cross subframe tentacles
My preference is to work through the pipes from the furthest points back to the manifold (rubber jointing block), then up through the sheath and back to the big green tank. This seems to get the manifold back into the right place.
The cross-car pipes are held in place at one end of the run with a single zip tie. The tie is loose and designed to hold the pipe back, not rigidly fix it in place.
The pipes then cross the subframe in another plastic sheath. Again, it’s worth coving the ends before drawing the pipes through the sheath.
The sheath terminates short of a looping metal bracket bolted to the subframe behind the long drive shaft.
I would suggest you undo this bracket for bet access but make a note of the additional pipes that are also guided by this bracket.
Extracting pipes
To bring new pipes in, I like to setup pulls or feeds using the old pipes.
Cutting the pipe off the manifold, I drill a 3.5mm hole, then tie some 1.5mm flexible wire to the end of the old pipe. I withdraw the pipe away from the manifold and the wire will follow the exact route of the pipe.
Hydraulic Octopus Pipe Bundle
The image above shows the buddle of hydraulic octopus pipes down the side of the engine. In the first image, the bundle is still taped up with yellow tape. Despite the age of the tape, the glue is still doing its job and won’t usually allow the old or new pipes to be slid past. I recommend that you remove this tape, and slide back the upper section of sheathing.
Engine bay disconnection
Depending on what features the car has, three or more connection may be made at the manifold on top of the LHM fluid reservoir.
At thirty-plus years old, the plastic here can be a little delicate. I recommend twisting the pipe with a very light grip from a pair of pliers to break the seal between the aged rubber pipe and the manifold outlet. Then, slide the pipe off. If the old rubber won’t turn with a small around of force, gently slit the pipe with a blade and peel back.
Return bundle replacement
When bringing the three or more hydraulic octopus pipes back up into the engine bay, I find it best to do all three together.
A slip not around the pipes using the wire pull helps to get a good grip, but if over-tightened, it will also damage the pipes.
To hold the not against the soft pipes without over-tightening, I apply a good wrap of tape. I use a type of Tesa tape that has high abrasion resistance. The outer finish of the tape makes it slide through the sheath much better than normal duct tape.
Drive Shaft
Both the Haynes and the Citroen workshop manual suggest taking the short drive shaft out.
I have to confess, I didn’t take out the drive shaft initially, as on the 1.4-litre engine car, I remember doing the job on first, I didn’t take the shaft out. I assume there was more room around the small engine, but I might have just been more nimble.
This also meant that I had to drop the gear oil, which I didn’t want to do, but I’m glad I did. Despite XPO having new gear oil just a few months earlier, the filth on the left is what came out, compared to the new oil on the right. I never thought to flush the gearbox as there was no oil when it arrived, but clearly, it was long overdue a flush.
With the drive shaft removed, there is plenty of room to access the myriad of connections around the front height corrector. Notice the failed pipe at the top of the height corrector? That is a new pipe! The angle at which I tried to fit the pipe caught a sharp lip on the metal barb of the corrector and tore the pipe. Good job that I took the drive shaft out. I’m certain this is where the original octopus failed, and there was quite a burr on the lip of the metal connection.
The dead octopus
I have to confess to being a fan of dissecting failed parts. I like to know what the failure point was, so that I can try to avoid the same failure point again.
However, having chopped the old octopus up in situ, I wasn’t expecting to find much
Laid out with all the severed pipes, it is clear just how hard and brittle the old pipe has become.
Amazingly, despite all the cut-off sections, I found one obvious hole. This split on the bend would have been facing into the subframe, so I don’t feel so bad for missing it.
Hydrualic Octopus Replaced
With the new octopus installed, does the car still leak?
Well, it’s hard to see with a still image, but with the engine running, I can confirm that the hydraulic octopus transplant has been a success.
Down by the replacement manifold and the area that was previously leaking, there is not so much as a drop! A few suspension cycles and lots of checking over the next few weeks will be needed. However, for now it seems all the fluid is staying where it should!
In the engine bay, the new pipes finish off the look of the otherwise very clean engine bay. A job well done!
With the hydraulic octopus replaced and the leaks solved, I’m almost ready for the first drive of XPO. However, the front wheels are a little cross-eyed and need some adjustment first!
M
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