Hi,
I have been reading comments on this forum for some time and have been gratefull for advice that many of you have taken the trouble to give.
I have a Xantia with a hydraulic pressure problem and hope that some one may have experienced similar problems or are able to point me in the right direction. The problem is with the accumalator in that when the car is set running after pressure has built up in the system the rear of the accumalator explodes with a loud bang and fluid is sprayed everwhere. Yes I do mean explodes and places a 1.5 inch split in the metal at the nipple end to the point you are able to see the internal parts of the unit. Two new accumalators have been destroyed.
Do you think this could be caused by the pressure regulator not cutting out or the pump continuing to supply pressure fluid to the unit bearing in mind that the pump was replaced only 6 months ago and has worked okay until now. Any comments would be appreciated.
P.S no other pipes have have been affected.
Xantia excessive hydraulic pressure
Moderator: RichardW
The pump works continuously, its just the pressure regulator that switches the flow back to the reserviour when there is full pressure in the accumulator/consumers. I can't imagine it's the pump.
The following site describes the BX hydraulic system, but appart from the hydractive parts, the systems the same as the Xantia.
http://www.tramontana.co.hu/citroen/sus ... spens.html
If you are interested in the hydractive side of things, check out, on the same site.
http://www.tramontana.co.hu/citroen/sus ... suspn.html
Which describes the XM system, which is very much like the Xantia.
//NiSk
The following site describes the BX hydraulic system, but appart from the hydractive parts, the systems the same as the Xantia.
http://www.tramontana.co.hu/citroen/sus ... spens.html
If you are interested in the hydractive side of things, check out, on the same site.
http://www.tramontana.co.hu/citroen/sus ... suspn.html
Which describes the XM system, which is very much like the Xantia.
//NiSk
I'd put my money on the pressure regulator being faulty, after all when you think about it 'regulator' so chances are it's not cutting out when it should.
Tell you what though, must be a scarey amount of pressure in there to do that!! I think normally they are at around 45 bar when they cut out, based on the set pressure of the accumulator.
I have actually heard of those spheres actually totally exploding in extreme cases which would leave a big & costly mess to clean up. I'd suggest get it off the road & fixed & FAST. Not trying to cause you any panic but as a safety precaution - a stitch in time.
Alan S
Tell you what though, must be a scarey amount of pressure in there to do that!! I think normally they are at around 45 bar when they cut out, based on the set pressure of the accumulator.
I have actually heard of those spheres actually totally exploding in extreme cases which would leave a big & costly mess to clean up. I'd suggest get it off the road & fixed & FAST. Not trying to cause you any panic but as a safety precaution - a stitch in time.
Alan S
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Dave Burns
- Posts: 1915
- Joined: 14 May 2001, 05:30
- Location: United Kingdom
- My Cars:
- x 2
Holy brown stuff, never heard the likes before, they usualy snap the drive belt or cause it to skid when the reg. goes ape.
Fiendish pressure to do that, the normal operating pressure is 170 bar (2465 psi) so you can at least double that taking the minimum of 2x safety factor in to account, but I think that being as its pressure vessel it will actually be much much more than this before it failed.
If its an early model with a flow distributor this could also have something to do with it, but the regulator is still the favourit in either type of system.
Dave
Fiendish pressure to do that, the normal operating pressure is 170 bar (2465 psi) so you can at least double that taking the minimum of 2x safety factor in to account, but I think that being as its pressure vessel it will actually be much much more than this before it failed.
If its an early model with a flow distributor this could also have something to do with it, but the regulator is still the favourit in either type of system.
Dave
This wouldn't be coincidental by any chance? Seems strange that if the other isn't leaking any more that this is.
The only times I really have ever had any problems with leaks from or around spheres has been when either I have incorrectly fitted the "O" ring to the sphere, someone has previously fitted incorrect type "O" rings (round type instead of square profile) or a sphere hasn't been tightened enough and with the pressure loss when stopped followed by constant increases when the car is started, it vibrated/wound its way looser.
May be worth investing a few pence in new "O" rings (I'm pretty sure Andys stock them) and just dropping the pressure out of the system, removing the spheres & refitting and tightening them. You should be able to tighten enough to seal with your bare hands. I have one car, an old CX that has worn in the threads on the front cylinders which can cause a problem, so whenever I take the sphere off, I use plumbers thread tape to refit it; one of those jobs I must get around to fixing one of these days.
Incidentally, you say in your initial post that the pump was replaced 6 months ago. Assuming it was either new or recond., have you referred this problem back to the supplier of the pump for his views also? I'm sure there would be some warranty on it & to contact them could be a wise precaution just in case further down the track any of these problems are sourced back to their pump.
Alan S
Edited by - alans on 29 Oct 2002 21:28:35
The only times I really have ever had any problems with leaks from or around spheres has been when either I have incorrectly fitted the "O" ring to the sphere, someone has previously fitted incorrect type "O" rings (round type instead of square profile) or a sphere hasn't been tightened enough and with the pressure loss when stopped followed by constant increases when the car is started, it vibrated/wound its way looser.
May be worth investing a few pence in new "O" rings (I'm pretty sure Andys stock them) and just dropping the pressure out of the system, removing the spheres & refitting and tightening them. You should be able to tighten enough to seal with your bare hands. I have one car, an old CX that has worn in the threads on the front cylinders which can cause a problem, so whenever I take the sphere off, I use plumbers thread tape to refit it; one of those jobs I must get around to fixing one of these days.
Incidentally, you say in your initial post that the pump was replaced 6 months ago. Assuming it was either new or recond., have you referred this problem back to the supplier of the pump for his views also? I'm sure there would be some warranty on it & to contact them could be a wise precaution just in case further down the track any of these problems are sourced back to their pump.
Alan S
Edited by - alans on 29 Oct 2002 21:28:35
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Dave Burns
- Posts: 1915
- Joined: 14 May 2001, 05:30
- Location: United Kingdom
- My Cars:
- x 2
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Jon
This is certainly very worrying, and the only time that I have heard of spheres actually exploding was a few years ago when there was a faulty batch of Belgium made pattern spheres, which were not correctly welded around the base.
A couple of years ago I did some "sphere destruction testing" using a ram from a porta power unit and a pressure gauge connected to the threaded part I cut off an old regulator.
Believe me when I say that the safety margin is considerable. We were able to exceed 500 bar (yes!) on Genuine spheres, and when they did explode it was in a controlled manner, peeling the metal away around the top nipple to release the pressure/fluid. We also tested our Amtex spheres (Lizarte)to similar pressures to ensure that they were made in the same way as the originals.
I would conclude therefore:
1) If the spheres in question are non Genuine, they may be faulty in some way
2) There is a blockage in the regulator (or its stuck)
3) The flow valve (if fitted) may be stuck.
4) I fail to see how the pump even unchecked can produce sufficient pressure to cause a sphere explosion.Usually, the pump belt will break first as an additional safety warning.
Dave, Alan, anyone?
Jon Wood
IT Supervisor
GSF t/as Andyspares
A couple of years ago I did some "sphere destruction testing" using a ram from a porta power unit and a pressure gauge connected to the threaded part I cut off an old regulator.
Believe me when I say that the safety margin is considerable. We were able to exceed 500 bar (yes!) on Genuine spheres, and when they did explode it was in a controlled manner, peeling the metal away around the top nipple to release the pressure/fluid. We also tested our Amtex spheres (Lizarte)to similar pressures to ensure that they were made in the same way as the originals.
I would conclude therefore:
1) If the spheres in question are non Genuine, they may be faulty in some way
2) There is a blockage in the regulator (or its stuck)
3) The flow valve (if fitted) may be stuck.
4) I fail to see how the pump even unchecked can produce sufficient pressure to cause a sphere explosion.Usually, the pump belt will break first as an additional safety warning.
Dave, Alan, anyone?
Jon Wood
IT Supervisor
GSF t/as Andyspares
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Jon
This subject interested me, so I just phoned a guy that rebuilds HP Pumps, Flow Valves, pinions and the like. A hydraulic Guru.
He tells me that he has seen Xantias explode spheres before, and an efficient HP pump can and will generate the pressure to explode a sphere IF THE REGULATOR IS NOT WORKING CORRECTLY. This applies to cars with a 6+2 pump and no flow valve.
Checklist:
1) Replace regulator and accumulator. Regulator should be new or quality recon, and be the correct one for the Xantia, NOT a BX one with the bottom cap turned 180 degrees.
2) If problem persists it can only be caused by a "dead line", that is a blocked high pressure pipe, the most likely culprit being the one from the pump to the Reg. Also when removing this pipe to check it for blockage, look at where it bolts to the pump (bearing in mind you had new pump fitted) that the LHM seal is not misaligned, blocking pressure flow.
Jon Wood
IT Supervisor
GSF t/as Andyspares
He tells me that he has seen Xantias explode spheres before, and an efficient HP pump can and will generate the pressure to explode a sphere IF THE REGULATOR IS NOT WORKING CORRECTLY. This applies to cars with a 6+2 pump and no flow valve.
Checklist:
1) Replace regulator and accumulator. Regulator should be new or quality recon, and be the correct one for the Xantia, NOT a BX one with the bottom cap turned 180 degrees.
2) If problem persists it can only be caused by a "dead line", that is a blocked high pressure pipe, the most likely culprit being the one from the pump to the Reg. Also when removing this pipe to check it for blockage, look at where it bolts to the pump (bearing in mind you had new pump fitted) that the LHM seal is not misaligned, blocking pressure flow.
Jon Wood
IT Supervisor
GSF t/as Andyspares
Dear Jon and all many thanks for your replies.
New regulator & accumaltor was supplied by Andy spares and is the Xantia type without flow control and specificly for this model of Xantia not the BX type.
It is strange that you mention the high pressure pipe from the pump as I have just been informed that this was recently changed when the pipe sheared off at the pump end and new was fitted. Certainly when I changed the regulator the pipe from the pump at reg end was not blocked or misaligned in any way. I cannot understand if the pipe was particially blocked at the pump end how this would generate excessive pressure in the system bearing in mind that the regulator should cut out when operating pressure has been reached?
I certainly will check the pump end.
Suspension sphere exploded after car had risen.
I will also check regarding the make of spheres and age.
New regulator & accumaltor was supplied by Andy spares and is the Xantia type without flow control and specificly for this model of Xantia not the BX type.
It is strange that you mention the high pressure pipe from the pump as I have just been informed that this was recently changed when the pipe sheared off at the pump end and new was fitted. Certainly when I changed the regulator the pipe from the pump at reg end was not blocked or misaligned in any way. I cannot understand if the pipe was particially blocked at the pump end how this would generate excessive pressure in the system bearing in mind that the regulator should cut out when operating pressure has been reached?
I certainly will check the pump end.
Suspension sphere exploded after car had risen.
I will also check regarding the make of spheres and age.
Dear Jon and all
Have checked the high pressure feed from the pump and there appears to be no blockage. Would it be possible that the sphere had already been partially damaged when the accumaltors were destroyed leaving the sphere weak and next in the pressure line?
Cannot find any paperwork for replacement spheres in the last two years, but they look relatively new. How can I tell if these are the wrong type or the manufacturer whos spheres were defective?
Have checked the high pressure feed from the pump and there appears to be no blockage. Would it be possible that the sphere had already been partially damaged when the accumaltors were destroyed leaving the sphere weak and next in the pressure line?
Cannot find any paperwork for replacement spheres in the last two years, but they look relatively new. How can I tell if these are the wrong type or the manufacturer whos spheres were defective?
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Dave Burns
- Posts: 1915
- Joined: 14 May 2001, 05:30
- Location: United Kingdom
- My Cars:
- x 2
Only if the suspension was set to maximum height would the suspension spheres recieve full accumulator pressure, at normal setting the height correctors would have cut the supply when normal height was reached.
You will have to examine the sphere's for any sign of the makers, fill pressure's, volume and damper sizes are usually stamped or printed on them, damper size normally being engraved near the damper orifice its self.
Dave
You will have to examine the sphere's for any sign of the makers, fill pressure's, volume and damper sizes are usually stamped or printed on them, damper size normally being engraved near the damper orifice its self.
Dave