One of my Xantias has blown yet another hydraulic pipe after about a year, and it lasted the same time as the previous one. It is always the same one, the main 6.35mm pipe between the pump and regulator block, always in the same area, the outside of shallow bend exiting the pump, before it gets to the pipe clip. The split is always longitudinal, never radial, so I can rule out vibration.
The current pipe is from Pleiades and is their standard kunifer pipe, not an OE steel pipe. They are aware that some Xantias seem to eat these pipes, not just the kunifer one, also the steel factory made items.
The pump on the car is in good order, the accumulator sphere is working OK and the hydraulics are working well.
Anybody got any ideas for these failures?
Handyman
Hydraulic pipe failure!!!!
Moderator: RichardW
Hmm,
A very unusual problem - definately not common. I'm just trying to picture where the split is occuring - how far from the pipe union ? Just a few cm's ?
A few suggestions:
1) It's important not to overtighten the nut where it goes into the pump - flare joints don't seal properly if they're too tight and it can actually damage them as well. The temptation is to do it up tight because it doesn't have a 'seal' like some of the other pipes, but really they only need to be nipped. (The same goes for the large pipes going into the Hydractive control block on HA2 models - too tight and they will leak)
2) Strain relief is really important - There should be no lateral or twisting strain on the pipe where it enters the pump - to do so you need to insert the pipe into the pump and nip the nut BEFORE attaching any of the clamps along the length of the pipe - the pipe should enter the pump squarely and without any strain needed. You should be able to tighten the nut most of the way by finger - if you can't its probably a sign the pipe isn't going squarely into the pump.
Then when you do go to attach and tighten the clamps, if they don't line up perfectly so that they can be bolted on without pulling the pipe out of position, take note of the error, undo everything, put a corrective bend in the pipe and start again with the pipe going into the pump. Rise, lather, repeat. When everything is right none of the places the pipe is mounted will have any strain.
3) I know I'm going to get a few nay-sayers here, but I just don't trust kunifer pipes. The few that I've seen used on high pressure lines on Citroen's have always failed (usually cracking) due to fatigue. There is a reason why Citroen use steel pipes for the original piping..... if you want to use kunifer then so be it, but don't be disapointed if a non-original material fails in a short time.
I find it highly unlikely that Xantia's "eat pipes" in this application, (sounds more like an excuse for why their pipes are failing) more likely is that it's a combination of incorrect installation of the new pipe (getting the strain relief on the pipe mountings correct) and/or kunifer not being as suitable for the job as steel.
You say the accumulator sphere is in good condition - but has this always been the case since the pipe was fitted ? Is it possible the accumulator was allowed to get right down low before replacing ? The strain from operating with a nearly flat accumulator may have stressed the pipe and then some time later after you'd replaced the sphere it may eventually fail.
Regards,
Simon
A very unusual problem - definately not common. I'm just trying to picture where the split is occuring - how far from the pipe union ? Just a few cm's ?
A few suggestions:
1) It's important not to overtighten the nut where it goes into the pump - flare joints don't seal properly if they're too tight and it can actually damage them as well. The temptation is to do it up tight because it doesn't have a 'seal' like some of the other pipes, but really they only need to be nipped. (The same goes for the large pipes going into the Hydractive control block on HA2 models - too tight and they will leak)
2) Strain relief is really important - There should be no lateral or twisting strain on the pipe where it enters the pump - to do so you need to insert the pipe into the pump and nip the nut BEFORE attaching any of the clamps along the length of the pipe - the pipe should enter the pump squarely and without any strain needed. You should be able to tighten the nut most of the way by finger - if you can't its probably a sign the pipe isn't going squarely into the pump.
Then when you do go to attach and tighten the clamps, if they don't line up perfectly so that they can be bolted on without pulling the pipe out of position, take note of the error, undo everything, put a corrective bend in the pipe and start again with the pipe going into the pump. Rise, lather, repeat. When everything is right none of the places the pipe is mounted will have any strain.
3) I know I'm going to get a few nay-sayers here, but I just don't trust kunifer pipes. The few that I've seen used on high pressure lines on Citroen's have always failed (usually cracking) due to fatigue. There is a reason why Citroen use steel pipes for the original piping..... if you want to use kunifer then so be it, but don't be disapointed if a non-original material fails in a short time.
I find it highly unlikely that Xantia's "eat pipes" in this application, (sounds more like an excuse for why their pipes are failing) more likely is that it's a combination of incorrect installation of the new pipe (getting the strain relief on the pipe mountings correct) and/or kunifer not being as suitable for the job as steel.
You say the accumulator sphere is in good condition - but has this always been the case since the pipe was fitted ? Is it possible the accumulator was allowed to get right down low before replacing ? The strain from operating with a nearly flat accumulator may have stressed the pipe and then some time later after you'd replaced the sphere it may eventually fail.
Regards,
Simon
Simon
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
Hi Handyman.
I would go along with Mandrake for most of the way, except that I find cupro-nickel pipe fine! used it for years.
Just a few pointers that I have come across before.
Is the pipe clamped down? I mean every clamp as they are all important for the vibration side of things.
When the pipe is fitted, does the pipe come out of the fitting with equal clearance all around? As if the pipe is touching the side of the fitting, then it will again vibrate.
How old is the accumulator sphere? The constant ticking can play havoc with pipes etc.
Hows your bending skills? gripping the pipe with pliers to hold it still and bend is not a good idea, as this can put in a weak spot, as will kinks. The best way to bend it is to pull it round a piece of tube, (heating it will not harm it)
Personally I have seen loads of these split and it seems that once they start they just keep on doing it, I use the cupro-nickel pipe from Pleiades and have great results, but in the past the odd one has split, some times the customer would insist that a genuine pipe was fitted, even so that split within a year.
Last time I was at Pleiades, they were talking of making a high pressure flexible pipe. Now that would be a brilliant fix, I dont know if they have done it yet? Might be worth asking though.
Regards
Slim.
I would go along with Mandrake for most of the way, except that I find cupro-nickel pipe fine! used it for years.
Just a few pointers that I have come across before.
Is the pipe clamped down? I mean every clamp as they are all important for the vibration side of things.
When the pipe is fitted, does the pipe come out of the fitting with equal clearance all around? As if the pipe is touching the side of the fitting, then it will again vibrate.
How old is the accumulator sphere? The constant ticking can play havoc with pipes etc.
Hows your bending skills? gripping the pipe with pliers to hold it still and bend is not a good idea, as this can put in a weak spot, as will kinks. The best way to bend it is to pull it round a piece of tube, (heating it will not harm it)
Personally I have seen loads of these split and it seems that once they start they just keep on doing it, I use the cupro-nickel pipe from Pleiades and have great results, but in the past the odd one has split, some times the customer would insist that a genuine pipe was fitted, even so that split within a year.
Last time I was at Pleiades, they were talking of making a high pressure flexible pipe. Now that would be a brilliant fix, I dont know if they have done it yet? Might be worth asking though.
Regards
Slim.
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Hello Slim and Mandrake, thanks for the replies, but your not telling me something I do not already know.
The score so far, two OE steel pipes and two kunifer pipes. One steel one split radially, and I would put that down to fatigue failure, but the others have all split longtitudinally in near enough the same area. The pipes last about a year before they give up the ghost.
Car is non-hydractive, has a good pump, good accumulator sphere and all the pipes have been stress relieved when fitted, all clamps and brackets are fitted, with good rubber inserts. Bends have been made with formers with no nicks or crimps in the pipes. I would not even think about using a set of pliers anywhere near the pipework. I do not bodge when it comes to spannering and after forty years of mucking about with things automotive I do not consider myself green or incompetent.
I spoke to Pleiades yesterday about it and we discussed all the options and possible causes. He is aware that some cars can consume these and is imminently due to bring out the modded flexible pipe. He did tell me about a new Xantia he had bought that had a flexible pipe fitted from the factory, so maybe it is a component failure that Citroen are aware of, but keep quiet about. Wish I knew the part number!
I must also add that I have had a similar failure with one of my CXs and that was an OE steel pipe that split.
Is this problem that uncommon?
The score so far, two OE steel pipes and two kunifer pipes. One steel one split radially, and I would put that down to fatigue failure, but the others have all split longtitudinally in near enough the same area. The pipes last about a year before they give up the ghost.
Car is non-hydractive, has a good pump, good accumulator sphere and all the pipes have been stress relieved when fitted, all clamps and brackets are fitted, with good rubber inserts. Bends have been made with formers with no nicks or crimps in the pipes. I would not even think about using a set of pliers anywhere near the pipework. I do not bodge when it comes to spannering and after forty years of mucking about with things automotive I do not consider myself green or incompetent.
I spoke to Pleiades yesterday about it and we discussed all the options and possible causes. He is aware that some cars can consume these and is imminently due to bring out the modded flexible pipe. He did tell me about a new Xantia he had bought that had a flexible pipe fitted from the factory, so maybe it is a component failure that Citroen are aware of, but keep quiet about. Wish I knew the part number!
I must also add that I have had a similar failure with one of my CXs and that was an OE steel pipe that split.
Is this problem that uncommon?
How old was the car the first time the pipe failed ?
If it lasted 5-10 years the first time but only one year each subsequent time its been replaced then it stands to reason that either the new pipes are inferior to the original, aren't fitted properly, or something has changed on the car that is causing damage to the pipes. As infuriating as it sounds, I can't really see any other possibilities
Presumably the pump is securely mounted so there is no movement between the pump and the engine - if so we should be able to eliminate physical movement as a cause.
And that only leaves over pressure. (Especially if the pipe has a longitudinal split)
Is the car an early one with a FDV or a later 2 output pump type ?
Just thinking aloud here - and I havn't studied the internal diagrams to see if its even possible, but I wonder if an (intermitant) fault in either the FDV (if you have one) or the pressure regulator could cause the pump to briefly run into a dead end - it would probably only take a second or two for the pipe to burst in that situation.
Normally when the pressure regulator switches it snaps quickly from one state to the other due to feedback between the two different control shafts, but if its possible for the control shaft to stop part way it may block the output of the pump. (Same might apply to a faulty FDV)
Another slim possibility is if the cut-out pressure of the regulator is much higher than it should be due to a fault in the pressure regulator...
Both scenarios seem very unlikely (but possible) to me, but then so does a pipe that keeps bursting for no apparent reason...
Have you got a spare pressure regulator on hand ?
Regards,
Simon
If it lasted 5-10 years the first time but only one year each subsequent time its been replaced then it stands to reason that either the new pipes are inferior to the original, aren't fitted properly, or something has changed on the car that is causing damage to the pipes. As infuriating as it sounds, I can't really see any other possibilities
Presumably the pump is securely mounted so there is no movement between the pump and the engine - if so we should be able to eliminate physical movement as a cause.
And that only leaves over pressure. (Especially if the pipe has a longitudinal split)
Is the car an early one with a FDV or a later 2 output pump type ?
Just thinking aloud here - and I havn't studied the internal diagrams to see if its even possible, but I wonder if an (intermitant) fault in either the FDV (if you have one) or the pressure regulator could cause the pump to briefly run into a dead end - it would probably only take a second or two for the pipe to burst in that situation.
Normally when the pressure regulator switches it snaps quickly from one state to the other due to feedback between the two different control shafts, but if its possible for the control shaft to stop part way it may block the output of the pump. (Same might apply to a faulty FDV)
Another slim possibility is if the cut-out pressure of the regulator is much higher than it should be due to a fault in the pressure regulator...
Both scenarios seem very unlikely (but possible) to me, but then so does a pipe that keeps bursting for no apparent reason...
Have you got a spare pressure regulator on hand ?
Regards,
Simon
Simon
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
Hmmm...
Simon & Slim really already said whats worth to be said on this problem.
I can add that the problem in no way is unknown, but OTOH not exactly common.
I've seen it myself on a BX, but that certainly was caused by missing pipeclamps over the pipe run. Besides the BX main pipe from pump is the early type with the wellknown Citroen terminated ends and seals - in 6.35mm version.
I tend to agree with Simon that the problem is down to either of 3 causes :
1) Citroen has lost track on material quality or specifications on later produced pipes.
2) Overly high pressure glitches is for some reason now present in the system on your Xantia.
3) Pump or regulator has lost the necessary rigid boltdown to the engine block.
ad 1 : lets see what Pleiades comes up with. They know their business ...
ad 2 : BX'es and early Xantiae had this odd 2-part rubber flexible pipe in the PAS steering circuit - exactly to dampen overpressure glitches. Meaning that Citroen was aware that overpressure glitches could exist in the system.
ad3 : Check if any of the pump & regulator parts and mounting details shows cracks or weaknesses. Check mounting bolts are torqued correctly.
The 6+2 pumps are known to snap their housing bolts during service life. Most often this problem however is accompanied with LHM leaks.
Simon & Slim really already said whats worth to be said on this problem.
I can add that the problem in no way is unknown, but OTOH not exactly common.
I've seen it myself on a BX, but that certainly was caused by missing pipeclamps over the pipe run. Besides the BX main pipe from pump is the early type with the wellknown Citroen terminated ends and seals - in 6.35mm version.
I tend to agree with Simon that the problem is down to either of 3 causes :
1) Citroen has lost track on material quality or specifications on later produced pipes.
2) Overly high pressure glitches is for some reason now present in the system on your Xantia.
3) Pump or regulator has lost the necessary rigid boltdown to the engine block.
ad 1 : lets see what Pleiades comes up with. They know their business ...
ad 2 : BX'es and early Xantiae had this odd 2-part rubber flexible pipe in the PAS steering circuit - exactly to dampen overpressure glitches. Meaning that Citroen was aware that overpressure glitches could exist in the system.
ad3 : Check if any of the pump & regulator parts and mounting details shows cracks or weaknesses. Check mounting bolts are torqued correctly.
The 6+2 pumps are known to snap their housing bolts during service life. Most often this problem however is accompanied with LHM leaks.
Anders (DK) - '90 BX16Image