C5 Mk3 suspension reservoir overflowed & car won't rise

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

citroen since 1973
Posts: 42
Joined: 01 Jul 2019, 23:35
x 6

C5 Mk3 suspension reservoir overflowed & car won't rise

Post by citroen since 1973 »

Hi everyone, after 6 months of normal use, after some of the hydraulic pipework was replaced near to the steering rack, my son now has another problem with my old C5 I gifted to him. Over last weekend he started the car up and noticed that the suspension didn't rise. He now lives 50 miles from me (and the indy garage that maintains the car), but I was popping down to do some work on his house yesterday, so had a quick look for a problem. There was no oil on the drive, which looked good, but the suspension would not rise when started. Upon opening the bonnet it was clear to see that there was fluid on top and around the reservoir, which looked like it was leaking from the cap. When removing the cap, it was full to the brim i.e. overfull, which it certainly hadn't been previously. Also, we don't recall hearing the normal sound of the suspension rising, when unlocking the car and starting it.
So, any ideas please? Also, is it possible to drive the car slowly (safely) in order to get it the garage?
User avatar
GiveMeABreak
Forum Admin Team
Posts: 28136
Joined: 15 Sep 2015, 19:38
x 3404

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by GiveMeABreak »

If the reservoir has been filled up with the car suspension at normal ride height, then the tank has been over-filled. As you probably know it must only be checked and filled between the marks on the lowest suspension setting.

If this has been overfilled, then it may have overpressurised the system and the electro pump may have blown a fuse due to over heating. I'd start be removing some excess LDS first, but be wary if you lower the suspension you may not be able to lift the car again until the issue is resolved. Then check the fuses.
citroen since 1973
Posts: 42
Joined: 01 Jul 2019, 23:35
x 6

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by citroen since 1973 »

Thanks Mark. It does seem quite strange to me, as the system, when last checked, was filled to the correct level mark. I'm afraid that the suspension is literally on the floor! No garage that my son tried could look at the car in the short term, in Worcester, so he very carefully drove it back to Telford late last night, when the road were clear. The indy garage he uses loves the car, but does admit that he is quite inexperienced with the model and the suspension. However, he is very keen, very honest and a great mechanic.
citroen since 1973
Posts: 42
Joined: 01 Jul 2019, 23:35
x 6

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by citroen since 1973 »

A little update - I spoke to the indy garage today and basically, he doesn't know what's wrong with my sons car! He says that the fuses protecting the pump are okay, but there appears to be no power supply going to the pump. I repeated the info I'd gleened from this forum, that overflowing fluid can quickly wreak the pump, but he just repeated that he thinks that it's a power supply issue and that he has no access to wiring diagrams for the car supsension system. He's now waiting for a colleague recommended mechanic, more aquainted with French cars, to have a look at it, but not until May! Modern cars - maybe we should all go back to bicyles!!!
Gibbo2286
(Donor 2020)
Posts: 5857
Joined: 08 Jun 2011, 18:04
x 1378

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by Gibbo2286 »

Did the master fuses get checked i.e. the ones under the under bonnet fuse board?

There are three wires to the pump two thick, a supply and earth and a thin signal wire, if you can get access to them (open the loom where it goes down at the front corner) and run a wire from the battery + to the pump + i.e. by-pass the usual run then apply 12v to the signal wire, needles pushed though the insulation will give to access for temporary connections, the pump will work if it's not faulty.
User avatar
GiveMeABreak
Forum Admin Team
Posts: 28136
Joined: 15 Sep 2015, 19:38
x 3404

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by GiveMeABreak »

I just hope by driving it on the floor that it has not caused damage to the system. It should be transported on a flat bed if the suspension has bottomed out, unless you can temporarily get a power connection to the pump long enough to get some pressurisation in the system. That may be enough for a careful drive at slow speeds as the pump normally only intermittently operates to maintain the ride height on these.
User avatar
Clogzz
Posts: 2097
Joined: 15 May 2005, 18:04
x 27

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by Clogzz »

The pump fuse is number 8 ... 40 Amps.
Pump_fuse_8.jpg
Gibbo2286
(Donor 2020)
Posts: 5857
Joined: 08 Jun 2011, 18:04
x 1378

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by Gibbo2286 »

GiveMeABreak wrote:
21 Apr 2022, 08:54
I just hope by driving it on the floor that it has not caused damage to the system. It should be transported on a flat bed if the suspension has bottomed out, unless you can temporarily get a power connection to the pump long enough to get some pressurisation in the system. That may be enough for a careful drive at slow speeds as the pump normally only intermittently operates to maintain the ride height on these.
I tried driving one only a couple of hundred yards and found it pretty unpleasant and bottoming out at the least bump in the road.
citroen since 1973
Posts: 42
Joined: 01 Jul 2019, 23:35
x 6

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by citroen since 1973 »

Thanks very much guys for your help and advice. I'll pass this on to the garage and report back.

I take your point about the driving it on the floor. Fingers crossed!!!
citroen since 1973
Posts: 42
Joined: 01 Jul 2019, 23:35
x 6

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by citroen since 1973 »

The indy garage has thanked me (YOU) very much for the additional information you provided. Thanks once again, Paul.
Hell Razor5543
Donor 2021
Posts: 12429
Joined: 01 Apr 2012, 09:47
x 1659

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by Hell Razor5543 »

Recently MY C5 threw me a 'suspension fault' wobbly. I eventually found that, although all of the fuses were fine, enough tarnish had built up on the fuse blades to stop the pump working (no power). I cleaned all of the fuse blades in the engine bay fuse box with an abrasive rubber block, sprayed contact cleaner into each fuse socket, and that sorted out the problem. In order to keep the electronics 'happy' I went through the BSi reset procedure, and cleaned the fuses while the battery was disconnected.
citroen since 1973
Posts: 42
Joined: 01 Jul 2019, 23:35
x 6

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by citroen since 1973 »

Good points, thanks James. Not sure I can answer your paranoid question though!
citroen since 1973
Posts: 42
Joined: 01 Jul 2019, 23:35
x 6

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by citroen since 1973 »

Further update - thanks to the help you have all given us, the indy garage realised that he had missed, what sound like, the master fuse. It now keeps blowing the fuse and it's been decided that the pump is wrecked. Costs to fix a new pump range from £700 for a second hand one, to £1700, for a new Citroen one. The car is now 14 years old, with little retail value, unfortunately it may be time to think of a replacement as it's cost my son quite a lot of money over the past 12 months.
User avatar
GiveMeABreak
Forum Admin Team
Posts: 28136
Joined: 15 Sep 2015, 19:38
x 3404

Re: C5 Mk3 suspension reservoir overflowed & car won't rise

Post by GiveMeABreak »

These can be taken apart and cleaned up. If LDS fluid has leaked into the pump casing along the seam it can mix with the carbon dust and cause a thick black paste that then shorts out the pump and blows the fuse.

Have a look at this post with pictures of a clean up. This is for a MK I/ II, but the principle is the same as far as the pump is concerned. Look at the article first as it will give you a good idea of issue.

viewtopic.php?p=423599#p423599

and here is a video of the full dismantling (just for reference but no need to go this far for a clean up)