Preemtpive maintenance for C5 (and similar) electric suspension pump motors

[octinum]

The dreaded "pump motor that blows the 40A fuse" thingy. Dear mods and admins, I did search the forum and wiki if someone else shared this, if this is duplicate, please feel free to delete. No offense will be taken.

Two Citroen-friends did all the work actually, I was not prepared, and I'm having some stiff back problems for some time now. So no credits for me except documenting it here.

In this mode of failure, the suspension pump starts blowing its 40A fuse. Starts with blowing after prolonged use (multiple up-downs for tire changing etc), then starts blowing every time the pump kicks in. Usually a higher amperage fuse seems to "resolve" the issue, which I have seen on C5s with dead pump motors.

What happens is, carbon "dust" from the motor brushes accumulate between copper conductors on the rotor inside. This causes the electric current drawn to rise, up to a point where it starts blowing the 40A fuse. The reason a higher amp fuse seems to resolve is, the current draw might have reached somewhere higher than 40A but lower than 60A. The internals and possibly the wiring is not designed for this, so prolonged use with the higher amp fuse can damage the pump motor and/or wiring irreversibly, meaning expensive repairs.

Considering the newest Mk1 C5 is around 15 years old, I recommend doing this even if you are not experiencing the symptoms and planning to use the car for some more years. The car we worked on is a 2005 Mk1 Phase 2 C5, with the 3.0 v6 engine. Before the work was carried out, the pump motor would blow the 40A fuse everytime it kicked in, meaning it would draw more than 40 Amperes. After the work, we measured less than 15 Amperes *under the same conditions*.

Note that you'll need to get the motor on the bench; so this requires depressurizing the system, removing front right wheel, wheel arch liner, dropping the right side of the bumper, removing the right headlight, and LDS tank. Others have much better instructions than I have for these, so please look for those parts of the process elsewhere.

Once you have the pump on the bench, open the cap using Torx bits (T20 or similar size). You'll see the brush assembly. Remove that too.

Here's how the rotor in my pump motor looked like:

See the "gaps" between the copper conductors? They are no more gaps, the dust from the carbon brushes filled between those. Clean them using thin plastic or soft metal "scrapers" (note: any help on describing this in English appreciated ). The next photo is from another C5 pump motor but it demonstrates the idea.

From top:

Give everyghing a thorough clean using an old toothbrush and brake cleaner/IPA (alcohol)/circuit cleaner. While at it, you can separate the pump portion and clean the internals, but that's a separate process which requires its own guide. Also found elsewhere. If you can solder, you can also replace the carbon brushes. On my case, the commutator (the assembly with those copper conductor parts on) had scratches and uneven wear. We leveled those as well with sandpaper, rotating the assembly with a power drill.

[aspire_helen]

Nice heads up. My C5 is 21 years old, and I live in fear of a suspension-related terminally expensive fault. I look forward to not having to do it, but I am now pre-warned. Thanks.

[myglaren]

I retired mine as it needed a new rear ram (hard to get) a new steering rack and a list of other smaller but not insignificant bits.
It was actually cheaper to buy a very nice (although not Citroen nice) Civic.
I just pretend it is French.

[Hell Razor5543]

I had to get a replacement pump from a scrapyard (for only £30!), clean up the motor, replace the (blown) 60A (wrong strength) fuse with a 40A (correct strength) fuse, and now the suspension is working properly. Fortunately the replacement unit was from a saloon C5 of the same spec and age as my estate C5 (so all I did after cleaning was to swap the valve control unit). I will probably strip and clean the pump some time in the future (probably on 31/11/2032!).

[octinum]

I am planning to use the vehicle for some time as cars in Turkey are extremely expensive especially when compared with the average income, and even worse when compared with the minimum wage. For context, a brand new base C3 with manual transmission costs around the equivalent of 60x minimum wage.

...a car that could reasonably replace the C5 is illogically expensive.

Anyway, let me get anecdotal. We're talking about this because Citroen, as any other maker, thinks the car is dead after 10 years. I think this is in line with governing regulations. The pump would most likely draw around 15 amps the day the car left the factory. With normal wear, this would increase naturally during the car's lifetime. They put a 40 amp fuse and designed the harness and all for this. After 10 years of use, the motor would maybe draw 30 amperes, or less than 40 anyway.

Mission accomplished. Owner should get a new Citroen.

In my and friends' experience, there are tolerances. I drove the car with a 60amp fuse for weeks in city traffic, flowing traffic, highway-like roads, and mountain roads. I think 60 amps is usable *if there is nothing else wrong* in emergencies, and even until end of winter. Temperature is critical, and the pump normally runs for seconds at at time, leaving ample of time for cooling. If it's cold outside, that helps too. I would avoid continuous use, without letting it cool down though, especially in summer temperatures. Like, avoid Citrobics.

[Hell Razor5543]

I would NOT have a 60A fuse where you should have a 40A fuse. Somewhere in her past (before I got her) my C5 had a 60A fuse fitted, and when it did blow it also damaged the bus bar in the maxi fuse box. Fortunately I was able to get a replacement maxi fuse box (from a scrap yard) for a few pounds. Even more fortunately the connector that went to the pump was not damaged, otherwise fixing that would have been very difficult.

I would remove the pump assembly, strip and clean the motor (brake cleaning fluid and a toothbrush did a good job on mine), and then you should be fine for several years (barring any LDS spillages). If you decide to do this you might also consider replacing the LDS reservoir at the same time. They can develop a pinhole leak (especially if she has been lifted off her wheels without the reservoir cap being loosened off first), and when the LDS gets into the pump motor it mixes with the carbon dust (from the brushes) and causes the main problem.