C5 X7 Suspension pump motor fault

[Greg2791]

Hi
Finally I got this issue as many of ye on this forum. I think overflow of hydraulic oil destroys the pump motor.
It started long time ago, however replacing 40A fuse from time to time was fixing it. I counted that I rather change my car sooner than its total failure, however this car drives so good, it is so economic, always bring me home and match all my needs that there is no point for me to change it. It worth to mention that is passes NCT seamlessly year after year.

Could you please provide me the pump assembly and motor part number , VIN : VF7**************[VIN obfuscated, can be read by forum staff].

Also I would appreciate of any tips and tricks that may be useful to replace /repair it. First of all, I will try to repair the motor, then I will be looking for replacement part.

Thanks
Greg

[Kees]

I hope, it's not to late, but you should done this the first time that the 40 A fuse was blown.
You can try to clean the brushes and plate from all of the carbon, and cross the fingers that you saved the pomp motor.
Greetings,
Kees.

[GiveMeABreak]

Greg, in future, please post your official part number requests on the dedicated Forum Here to ensure your post won't be overlooked or not seen by staff.

The pump is not sold separately, it is sold as part of the complete Hydraulic interface:

(1) Suspension Hydraulic Block (Unconfigured - requires configuring with Diagbox), part: 5277N8, £2011.67
Suspension Block (Standard Exchange part - requires configuring), part: 1680917280, £1289.92

[steveclv]

Now you have picked yourself up off the floor having seen the PSA prices, I can strongly suggest that you search YouTube for some videos on dismantling and cleaning the pump. In many cases it's leaking LDS that has penetrated the motor and this mixes with carbon residue from the brushes creating a electrically conducting paste that shorts out the motor and blows the fuse. A good clean with brake cleaner can fix it.
If that is not possible then get a replacement from a breaker/dismantler - around £150. You then need to use the electrical box from your old one with the new pump (which you clean before installing!!!) so that it does not need recoding with Diagbox.
Hope that helps.

[Greg2791]

Thank you for your advice.

I have good news: I was able to fix the issue at no cost except for my time. It was a relatively straightforward task, although quite messy.

The problem was caused by an excessive amount of oil and graphite mixture inside the motor. After cleaning the interior and sanding the commutator, everything returned to normal.

Here are the results of my careful motor examination:

Motor Electrical Measurements:

Resistance between commutator slots: 0.3 Ohms
Inductance between commutator slots: 55 uH
Resistance of commutator to motor body: >Megaohms
Motor Current After Repair:

Free run (no pressure built up): 4 Amps
Low to 1st position: 10 Amps
1st to 2nd position: 15 Amps
3rd position: 20 Amps
These measurements can be used as a reference to assess the health of a similar motor/pump.

It's worth noting that after the repair, it took approximately 10 minutes for the pump to lift the car. I primed the pump by adding a small amount of oil to the oil supply pipe before reconnecting it to the tank.When the pump was running and there were no signs of the car lifting, I decided to pressurize the tank by covering the entry by hand and using the air gun observing a slight tank swelling. After a few minutes, the current started to increase, and the car began to lift.

[steveclv]

Excellent news and yes, that's the way that many pumps can be repaired relatively easily as long as they are done before the 40a maxi fuse blows too many times - when it blows it's a sure sign that the pump is contaminated.
To re-prime the pump you need to apply 0.5psi pressure to the tank (which you have done). Leaving the pump running without pressure can burn it up although the BSI does have a timer built in to prevent this from happening (allegedly).
Another C5 rescued

[Coney]

Did that back in 2017 and haven't had any problems again to this day.

[Vladimir1977]

Me too in '19, on 2007 c5 mk2 and still running fine.
All you have to do is to keep the pump motor dry from lds.