C5 X7 rear suspension fun.

[GiveMeABreak]

No worries, but Chops, mash, peas and gravy with a glass of OJ for me tonight.

[Manuel]

Tengo un problema igual con el citoen c5 x7, y no se como poner las mediciones en el escáner, si alguien me puede ayudar estaría muy agradecido


"I have the same problem with the Citroen c5 x7, and I don't know how to put the measurements in the scanner, if someone could help me I would be very grateful"

[GiveMeABreak]

Utilice inglés para publicar en este foro. Puede usar Google Translate si el inglés no es su idioma nativo.

You need to undertake the measurements then the calculations and ultimately enter the values into the suspension ECU with Diagbox or Lexia.

[MrBerlingoC5]

Hi,

I am new to this forum, but not to French cars. They have given me much joy and much suffering. Life is a rollercoaster.

I just picked up a 2011 C5 (2.0 HDI) this week to add to my collection. But of course with my luck, the suspension failed and sank down while I was driving home from the dealer...

It turns out the previous owner had the original hydraulic pump fail in 2021, replaced it with a used ebay unit which also failed on him 2 years later, replaced it with another used ebay unit which has now also failed on me 6 months after the previous swap. The current pump details:

This thread has been extremely useful so far in troubleshooting, the contributions from Marc and many other folks are very insightful!

So the status now, I was able to remove the hydraulic pump and indeed it had the seemingly common issue with the oil/carbon dust mixing into a paste and fouling up the commutator (top level symptom was the midi fuse that protects the motor blowing). As an engineer it upsets me that Citroen did not design a seal here to prevent the oil ingress. I have cleaned this up with IPA and shop air and the motor now runs fairly freely when it is separated from the pump itself.

But there was a lot of resistance on the pump when I tried to rotate it. So I have stripped apart the central bore of this now also.

The only obvious issue that jumped out at me was the diaphragm at the oppisite end of the pump to the motor, is this an accumulator of some description? I would assume it is smooth the pump outlet pressure. Anyway, the diaphragm was quite deformed unsymetrically and had frayed, releasing some bits of NBR? into the oil. Hopefully these haven't blocked any of the lines elsewhere in the system.

So my questions after this entertaining week of troubleshooting my new steed.

0. The LDS oil that drained from the small outlets was quite cloudy, is this normal? The LDS that drained from the resovoir was nice and clear. They only replaced it 6 mths ago. The car had been standing from 1-2 months before I bought it.
1. Can we buy individuals spares for these pumps anywhere? Ideally I would just replace this diaphragm to start with as it could be a very cheap and handy fix then, any ideas for a part number or a supplier? (In my searching I only found complete pump units with quite high prices 400-700€ even when 2nd hand with 200'000+ km on them and in "mystery" condition. Or brand new ones for 1500-2000€, which is almost half the price of the car...).
2. My motor did not have a smoothing capacitor between the +/- terminals that I have seen in some peoples pictures. Is this normal?
3. Two of the brushes are significantly more worn than the others. This seems odd and I am not sure the reason?
4. Should I strip apart the solenoid valves also to clean out any debris from the failed diaphragm?
5. Are there any other reasons I am possibly overlooking that would cause the pump to have resistance while trying to rotate? I can only think perhaps if the solenoids were all stuck closed the pump would be just trying to dead-head and load up the motor until the fuse blows?

Cheers!
Alan

[MrBerlingoC5]

An update to the fun. I was able to swap in a replacement pump from eBay that was in nice condition (I got lucky, it is 2015 vintage and barely used, no gunk on the brushes and still full of life). I used the original electronics unit from my car to ensure no reprogramming was needed.

I applied a tiny bead of sealant around the shoulder where the pump housing parts bolt together. This should hopefully give some more insurance against the oil ingress issue.

I don't have a Lexia or a way to toggle the individual solenoid valves in-situ, as per the bleeding procedure suggested. But I was able to achieve a partial bleed by simply cycling the "up" and "down" buttons with the motor power disconnected, applying ~0.5 barg to the LDS resovoir while pressing the "up" button. I was hoping this would cycle the soelnoid valves and push through any air back to the resovoir when "venting" with the "down" button. After several cycles of this I connected the motor power, the pump runs fine and the back of the car raises up! But the front refuses to rise. I tried opening the bleed nipple on the top of the front right suspenion strut. A little burp of air came through and then some cloudy LDS (being cloudy I assume meant it came from the pump with some air still entrained).

My next step is probably to take it to a Citroen garage to get the system re-bled by them and adjusted if needed. Unless anyone here has some other insights or ways I can try it myself?

Cheers,
Alan

[myglaren]

With the engine running, turn the steering wheel full lock in one direction, then full lock in the opposite direction, repeat a few times, don't pause at full lock, keep the wheel moving fairly slowly.

[Sloppysod]

With the engine running, turn the steering wheel full lock in one direction, then full lock in the opposite direction, repeat a few times, don't pause at full lock, keep the wheel moving fairly slowly.

Also keeping it pressurised as you did earlier will help.

[MrBerlingoC5]

Awesome tips guys! After about 10 lock-to-lock of the steering the front suspension worked like a charm.

Now the final boss level.... the position feedback doesn't work and it can only go from full down position to the full up position. I suspect the previous owner/garage that worked on this messed with the position or the settings of the feedback sensors while trying a quick fix on the pump fault.

Will update when I get some diagnostics on it and can check the settings of the feedback sensors.

[MrBerlingoC5]

Update: well it seems the car just needed a nap to think about it's feedback sensors. The next morning I took it out for a short drive and hey presto full control again! It does "seem" a little high to my eye. I would need to check the measurements of what the "normal" position should be.

Now the next little jobs to adventure into are a new front wheel hub (threads stripped on one hole) and maybe some new brakes and tires