C5 X7 Front strut change today

[aerodynamica]

Hi all, my plan to start work on the rear suspension was scuppered by the sudden leaking of the front left strut. This was the original factory item whereas the OS one had been replaced at some point just before I took the car on last December. The manufacture date 2018 is clearly seen etched on the casting at the strut top.

I searched for and was pleasantly surprised to find the strut available (although the first one found on ebay from a Citroen garage was cancelled by the seller due to being out of stock..)

I didn't find it too difficult to change apart from the 3 upper fixing torx screws were seized. I opted to remove the upper strut plate with the strut itself.

Anyway I took photos for my records and here's a few:
New LH strut.

2022 manufacture date!

The old, leaky strut.

Lower end where it leaks.

Comparing old and new:

Upper spnge vibration buffer quite degraded on the old strut

Refit:

Clean up of the strut mounting and upper arm. Suffering some galvanic corrosion like most of the X7..

Bled and repressurised the system and all good.

It's kind of bad that the hydraulic struts are not repairable like they were on all LHM citroens. You could replace the outer rubber bellows etc fairly easily. It's strange that the old LHM system was kind of 'allowed' to leak fluid that was caught in the rubber bellows and slowly fed back to the LHM tank. The X7 doesn't have this arrangement although I think the C5 I and II did. Anyone know how the X7 set up works? Do all four hydraulic struts simply not leak at all and hence don't need the low pressure leakage return circuit? Just curious really.

Unfortunately the car is beginning to show sign the front NS wheel bearing is going..... What next!

[MattBLancs]

Unfortunately the car is beginning to show sign the front NS wheel bearing is going..... What next!

Apologies if stating something well aware of, but check the lower bearing (FRIP bearing?) As these can give play too I believe, could be mistaken for wheel bearing play??


Thanks for great pictures. Excuse my ignorance - is that the common failure mode for these then? I've read of "leaky struts" = unrepairable but hadn't realised it was the steel corroding (had in my head some odd unobtainable seal, right in the heart of the strut was what wrote the strut off!)

Might slap some paint on whatever I can get access to in a bid to delay the inevitable,

Matt

[aerodynamica]

Hiya Matt, well it's only my understanding of how it leaks. It seems to be that the rubber outer boot that is kind of loosely fitted along the strut length but fixed at each end upper and lower. Mine has a small gap at the lower end where the rubber has come away from the metal. It is likely caused by the corrosion but not certain because it might simply have detached from 14 years of vibrations. Anyway, slapping some thick paint on won't hurt. I took the opportunity to give the upper wheel arch a few coats of hammerite since the wheelarch liner was out.

As for the lower bushes - these were replaced back in January and still look good. What happened was that after 10+ miles this morning and on the M-way I began getting a vibration similar to an out of balance tyre but it came on gradually. I stopped at the services and looked around and found that the NS front hub was hot whereas the OS one was barely warm. Also, the 25 minute stop seemed to 'cure' it because when I rejoined the motorway and traveled a few miles at the same speed the vibration didn't return. Then A roads to the workshop no further issues. Seemed to be a few miles of motorway that showed up the symptom that seemed to cool off with the break.

It just seems likely it's the wheel bearing and not a brake binding for example just going by the heat I found. Will give it a bit of time before I totally blame the wheel bearing..

[MattBLancs]

Not saying impossible, but I'd think a wheel bearing failing generating a noticeable amount of heat seems unlikely to my mind - brakes are friction generating devices, so one that is playing up does need much change before it is getting hot. Whereas a wheel bearing is specifically intended to minimise friction and starts off with a good dollop of grease to help it do so - on that basis I'd be surprised if the bearing was generating much heat without being very obviously unwell in other ways (e.g. massive play - and unlikely that play would disappear after a rest)

Sometimes brakes can stick sometimes and not others, knocks and thumps as driving along seemingly knocking it loose again and the binding disappears (for a while. I had a rear brake seize on (2007 C4 about 160000 miles at the time) grinding noise continued whilst moving, pulled into a layby, stink of hot friction material, alloy wheel got to the touch. Absence of tools, so gave the caliper a wallop through the gaps in the wheel spokes with the end of the wheelbrace = no more noise, no more smell, wheel not much hotter when I had got the remaining (~60 miles) trip home!

I'd take pads out, wire brush, bit of copper/ ceramic grease on the sliding surfaces as first thing, is an "almost free" fix if it cures it

[aerodynamica]

Ha thanks, come to think of it there was a hot 'brake-ish' smell from the same hub noticed while changing the suspension strut..

[KennyW]

Graeme,
the sticky caliper will return to haunt you. I found mine was caused by the rubber seal protecting the caliper piston had worn over the years allowing egress of water and grit.

Repair kits readily available and easy to install kits costs about £20 comes with all the seals, new piston and bleed nipple.

Kenny