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Suspension gone hard - crashing on bumps |
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gmerry
 
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   Member No: #21
Location: Scotland |
Hi all, anybody have a clue as to where to start with the following:- Suspension has gone much harder, (just on bumps, still floaty on smooth stuff), with a noticeable crashing on medium sized obstacles. Lexia does not indicate any faults and still shows suspension to be on "soft" mode. Hydraulics can still raise and lower car. A short while ago I depressurised suspension and removed the excess LDS from the resrvoir but these symptoms did not occur until 10 days after that. Regards G |
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C6Dave
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  Member No: #1
Location: Northumberland |
Is it coming from any particular corner G? | ||
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cruiserphil
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 Member No: #38
Location: Celbridge |
G., Did you try the variable damping test on Lexia, which checks the operation of the servo motor ability to switch damping on the struts? If there was a possibility of a servo motor fault (as in stuck) it might show it. Regards, Phil C. |
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gmerry
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Member No: #21
Location: Scotland |
Thanks for replies: it did cross my mine that a sphere may have gone flat but car seems reasonably level so I think I can rule that out. Maybe the problem is in the front but to be honest hard to tell. It kind of feels as though the additional centre spheres are isloated ()as in sports mode) The servo motor test sounds like the sensible next step. Regards G |
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travlician
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 Member No: #350
Location: Paradera |
A flat sphere on a suspension strut will not result in being the car not level. The servo test will show that (although you will not distinguish a flat sphere from a damaged servo easily). Maybe the suspesion "learned" to be firmer? Another factor to consider is air in the hyraulic system, happend to me after leaking and driving with less LDS than should be. |
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gmerry
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Member No: #21
Location: Scotland |
Phil, based on your suggestion, I've cycled each corner damper between hard and soft and pushed the car and yes, on soft the car bounced up and down and on hard, couldn't hardly budge each corner at all. So The variable dampers must be good. The other suggestion related to air in the hydraulic oil. Recall that I had to remove 500ml from the suspension when it was depressurised. At the time I was surprised how much air was in the LDS and I just thought this was normal due to pressure releasing. But now I'm thinking that the reason there was so much volume wanting to overflow was because of all the air bubbles getting into the oil. So how is the air getting into the LDS? Anyway I've added 250ml of LDS to see if that cures the hard suspension. Will need to track down source of air in LDS Anyone else noticed extreme aeration in the LDS after depressurisation of the hydraulics via Lexia? Regards G |
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gmerry
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Member No: #21
Location: Scotland |
Hi all, suspension is no better: hard to describe but feels like hard springs and soft dampers. As pointed out, air in the hydraulic fluid may be the probvlem so I will try the bleeding procedure. This requires the Facom 920 tool which I'm guessing is a regulated air supply set to 7psig (1/2 bar). Anyone have a better guess or know what the FACOM 920 tool actually is. Regards G |
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gmerry
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Member No: #21
Location: Scotland |
Hi all, more convinced than ever that I have a failed sphere in the system. No reported errors from position sensors (info rapid on corroded connectors that results in hard ride) and handling on car is very very strange. I spoke to a very knowledgeable chap called Doug at Westoen who pretty much said that if the LDS has gone "brown" due to mass of micro nitrogen bubbles then that would indicate a failed sphere. Now which sphere? The C6 has 7 of them (one for each corner, two for the rear axle stiffness control and 1 for the front stiffness control) so I may get the stiffness sphere's off and send them to Doug for testing. Anyway part numbers for future reference (6 Cylinder cars only): Front 50 bar, 5276 10 or Munroe aftermarket SP8133 two off Front Active Suspension 70 bar 5276 27 or Munroe aftermarket SP8136 one off Rear 40 bar, 5272 81 or Munroe aftermarket SP8132 two off Rear Active Suspension 40 bar 5272 81 or Munroe aftermarket SP8132 two off Rear Spheres are all the same. Apparently there is no direct diagnostic indication of a failed sphere. Apparently for the smug Lexus owners out there they have pretty much the same problem with their Hydropneumatic suspensions too. Regards G PS, a possible supplier - Click Here - |
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mark28
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  Member No: #102
Location: Hampshire |
There us a tool used to test spheres on older Citroens that does fit the C6 not sure which one but I was told about it by mechanic whilst mine was in the garage again ! As for smug Lexus owners , I would give my left arm to have a car that has a failed sphere every so ofter, rather than the list of issues I have had with my C6 ! |
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smorphet
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 Member No: #88
Location: Hertfordshire |
Your description of hard springs and soft dampers sounds very familiar. In my case it turned out to be a failed front nearside sphere, but it took a while to diagnose. Initially, Lexia was showing a fault from a front static pressure sensor. Eventually, after replacing many sensors, ECUs, etc., the garage pressure tested the spheres and found the problem. As I understand it, the damping is all in the corner spheres, but the springing is shared with the centre sphere. Losing the centre sphere would just be something like having the suspension switch into 'hard' mode. Losing a corner hardens the suspension in a similar way, but since all the work is now being done by the un-damped centre sphere, there is no damping. As you describe, this leads to very strange handling - crashing on bumps, but then wallowing and pitching in corners. I think in my case, in addition to all the red-herrings, there was a genuine failure of a rear height sensor at some stage. Whether this contributed to the symptoms at all, I'm not sure. Steve. |
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gmerry
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Member No: #21
Location: Scotland |
Hi Smorphet et al, I changed out my two front suspension spheres. They both make a rattling sound when shaken. Can't imagine this is correct. Now have two Monroes SP8133 (50 bar) fitted up front. Will test drive and if still not correct, will try the front stiffness sphere next. Regards G PS, will make up a sphere tester at some stage. |
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Junksleeper
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  Member No: #1605
Location: Staffordshire |
I have a very similair problem on my 07 plate 2.7 exclusive, ie hard suspension at low speed especially over speed bumps and the like and after taking it to local Citroen/Peugot specialist was informed that as well as having the aforementioned smorphet's experience of a diagnostic showing a fault from a front static pressure sensor, the rear nearside suspension cylinder was leaking and needed replacing at a cost of £350 (part specially ordered from France)- sharp intake of breath! I've read on a few C5 forums that these cylinders have seals and gaiters that are replaceable for a lot less than £350 notes. I've also read that they are supposed to bleed to lubricate the cylinder. Can the same be said for C6 suspension cylinders? The garage state that without replacing it , it will not be possible to trace the suspension fault. I'm almost resigned to spending loads of money and ending up getting nowhere in fixing the initial problem. I'm not overly keen on replacing sensors unnecessarily. There seems to be conflicting advice as to how to actually test the spheres which would seem to be the easiest and quickest way of eliminating or tracing faults. Any ideas out there? Any help from you guys will be very much appreciated. 
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C6Dave
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Member No: #1
Location: Northumberland |
Lots of posts already on suspension spheres which are likely to be the problem, not a sensor. | ||
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dsharples
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 Member No: #119
Location: Woodbridge |
Dave, absolutely agree. My experience is that some dealers and specialists are adamant that the grey saucer-spheres don't fail or decrease in pressure over time, because they "have never seen any". Many C6 owners can state the reality is quite different. I can only assume that its because many C5/C6 owners cars are now reaching the age (outside of dealer maintenance/warranty periods) where the ride is becoming truly awful, and are seeking a solution, or that the cars are now in the hands of enthusiasts who know its not right... And of course, sphere pressure/failure can't be detected by Lexia/DiagBox. So this could be a new "learning" for all... |
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Mike H
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 Member No: #53
Location: Melbourne |
I agree, 8 years 88k kms. Per these posts I had all spheres changed to IFHS kit. Very reasonable price Much improved ride Do this first. You can send the old set for regas. Mike |
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