Citroen C5 MK1 hot suspension strut

[Farmcow1]

Hello everyone, I've been been having height corrector problems with my C5, but I think we may have sorted the electrical side of things.
While testing the suspension, I was raising and lowering it for awhile, just happened to touch the passenger side suspension strut and it was hot, while the driver side was cool, . the suspension goes up and down (about an inch)in the road setting (green on dashboard)and does the same on the next heigher setting ,but stayed solid on the top setting...
Could the heat in the strut and the movement be due to it leaking oil back to the tank and not gaining pressure in the strut!!!?? Thanks Rod

[GiveMeABreak]

If there is heat being generated - that may indicate a pressure restriction somewhere or a blockage possibly, so the excess fluid may returning more rapidly back tot he LDS tank - I think I recall you saying this side was a little more damp about the strut than the other side Rod IIRC. It is possible of course that there has been some damage to the strut if the car has been driven without any pressure in the front. I recall you mentioning that it looks like the underside has been scrapped at some point. If this was the case then a nasty jolt could of damaged the strut internals - and account for the heat being generated. If you're going to consider a strut replacement, and need the part numbers, just shout.

[white exec]

From a physics point view, the fluid there will be non-compressible, but any trapped air will heat up when compressed, and transfer its heat to the strut casing.
Or some unwanted friction?

[Farmcow1]

Hello again Marc ,I
would appreciate the part number.I think a change of strut is the best way forward, could I just ask one more favour (question)
What do I need to do to 1_jack the front wheel
2_depressurise the system
3_ anything else you think I should know
4_finally many thanks again ,Rod

[GiveMeABreak]

I'll put up the procedure for replacing the strut along with the parts info Rod - just having supper, so will lock this thread until I've uploaded everything..

[GiveMeABreak]

So here is the parts diagram, and as I mentioned when we spoke rod, the struts are no longer available from Citroen now, so looks like a second hand one. The part numbers are:

Left Strut: 5271H4
Right Strut: 5271H5

Make sure you have some LDS fluid. Thera re 2 ways of doing this - one removing the cylinder and sphere - or the cylinder only - I have listed both for you.

So it is possible to depressurise the front and rear axles independently, without using Lexia that would do this electronically for you.

I would ensure you get the car somewhere easy to work on and on axle stands at the front.

Removing / Refitting a Strut on a MK I C5

Recommended Tools

[1] Spanner for removing "slimline" spheres 8611-T.	[2] pivot spreading tool 8601-T.K.	[3] adaptor for angular tightening 4069-T.

Removing

Manually depressurising the Circuit (H3 only not H3+!)
(Note - both Front and Rear shown here for completeness Rod - but you only need to worry about the front axle for the front strut job)

Depressurising the Hydraulic Circuit (Front & Rear)
ESSENTIAL: Any LDS fluid recovered must not be re-used.
Collect the LDS fluid so as to keep the working area clean. Respect the environment.

• Start the engine.
• Set the height control to the "LOW" position.
• Stop the engine.

Front suspension: Undo the detensioning screw (1) by one turn. Wait for the pressure in the hydraulic circuit to fall fully.	Rear suspension: Undo the detensioning screw (2) by one turn. Wait for the pressure in the hydraulic circuit to fall fully.

Removing / Refitting a Strut on a MK I C5 (continued)

• Slacken off the road wheel screws.
• Lift and support the vehicle with front wheels suspended.
• Remove the wheel.

Uncouple the anti-roll bar ball-joint (1). Remove bolts (2). Position the tool [2] in the pivot aperture. Turn a quarter turn to open the pivot. Uncouple the return pipe (3).	Removing the suspension cylinder with its head Uncouple the supply pipe (4). Remove: The nuts (5) The suspension unit

Liberate gaiter (6) upper section. Unscrew nut (7). Detach the cone by means of a cast bronze hitting implement. Remove the suspension cylinder.

Refitting

Refitting the suspension cylinder with its head

Put the suspension unit into place.
Tighten the nuts (5) to 4,3 ± 0,6 daN.m.
Couple the supply pipe (4).
Hydractive suspension 3 Tighten to 1,2 ± 0,3 daN.m.
Hydractive suspension 3+ Tighten to 2,5 ± 0,6 daN.m.

Refitting the suspension cylinder only
Remove the scuttle grill

Check the presence of the stop (8). Oil the tapered part at "a" as well as the seal contact face. Refit the suspension cylinder. Tighten the nut (7) to 5 ± 0,5 daN.m. Angular tightening 65 ± 5° Using tool [3]. Coat the threads with a few drops of LOCTITE FRENETANCH. Reinsert gaiter (6). Refit the scuttle grille. Position the tool [2] in the slot in the pivot. Turn a quarter turn to open the pivot.

Respect the positioning of the cylinder in relation to the pivot. The boss "c" enables correct angular positioning by engaging in the slot "d". N.B.: The boss "b" serves as a stop. Fit the bolt (2) (new NYLSTOP nut) Tighten to 5,4 ± 0,5 daN.m. Recouple the anti-roll bar ball-joint and tighten Tighten to 6,4 ± 0,6 daN.m. Connect the return pipe (3). Fit the wheel. Return the vehicle to its wheels. Tighten the wheel bolts. Bleed the suspension circuit (refer to me previous post).

[411514]

While testing the suspension, I was raising and lowering it for awhile, just happened to touch the passenger side suspension strut and it was hot, while the driver side was cool, . the suspension goes up and down (about an inch)in the road setting (green on dashboard)and does the same on the next heigher setting ,but stayed solid on the top setting...
Could the heat in the strut and the movement be due to it leaking oil back to the tank and not gaining pressure in the strut!!!?? Thanks Rod

Seems unlikely that significant heat would be caused by fluid flow/restriction - how many times did you raise and lower?

Is this front or rear we are talking about. If front - did you do this after driving the vehicle? If so, I would suspect a binding brake caliper heating the strut. Binding brake would also account for problems with raising/lowering suspension.

[Farmcow1]

Hi Sam, thanks for reading my question, the car was stationary when testing the height setting and the brakes were not involved, I raised and lowered it about 6-7 times over about 20 mins,as the strut (front passenger side)got hotter the oil return pipe also became quite warm, but like I said the other side was cool. Thanks Rod

[GiveMeABreak]

For clarity - the vehicle was trailered after purchase - so history is not really known and won't be brake related as it's not been driven - and is getting warm / hot when stationery on the passenger strut only after trying to raise and lower.

As for the heat issue... this is taken from general troubleshooting on worn components of hydraulic systems in general - which is what I was trying to convey - if an internal component has failed / failing or damaged (Rod mentioned there was more of a leak on this strut than the other). The vehicle at some point has been scraped along the floor from visible signs.

As components wear, internal bypassing increases. Oil that bypasses across the tight tolerances of a component undergoes an immediate pressure drop that performs no work. Heat is the inevitable result. The more bypassing that occurs, the more heat is generated. Some components are notorious heat generators even when brand new. Servo valves, proportional valves and flow controls all generate heat from the time they are new because they always have a pressure drop across them. So how do we know if a component needs to be replaced in order to keep the temperature down? The best way is to routinely measure the temperature gain at various components in the system. Keep a record of these measurements and use them to help locate troublesome worn components.

The above from GPM Hydraulic Consulting.

[Farmcow1]

Hi Marc, Wow that's a good bit of research!! That puts my mind at rest about the heat generation, Thanks again Rod. PS( have found a used strut and shall be fitting I next couple of days, I'll let you know what happens)
Sorry meant to ask ,can I put the car in high setting ,then support the front on stands, then put it in lowest setting to do the strut replacement,or will this upset the suspension??

[GiveMeABreak]

Ok, so yes - raise the car - get the axle stands under, then you MUST put the suspension in the lowest setting, and only then depressurise the front axle as per the guide above. - Obviously don't forget to tighten up the screw after

Good luck with the replacement strut Rod.

[411514]

When the car reaches the top of its movement does the pump stop running immediately, or does it run on after the height has stopped changing?

[Farmcow1]

Hi Sam ,the pump stops when it reaches the heighest position ,but runs on and off pumping the car up and letting it fall and up again and so on and on (it does this only in road height setting and the next one up) so I can only think there's damage some where in the strut. Rod

[Farmcow1]

Hello everyone ,just an update on my hot suspension strut. I changed the strut and now everything works as it should!!. I would like to thank everyone who helped with my problem, especially Marc, thanks Marc for all your time and help,cheers, thanks again, Rhod

[GiveMeABreak]

Da Iawn Rhod. Glad you have sorted it and hopefully can employ the car now. A really tidy example of a MKI which looks like new.