C5 (X7) Suspension Pump Motor service (removal and cleaning)

[EDC5]

As I've mentioned in precious threads, the 40A maxi fuse had blown on my X7. After I replaced it the car seemed to behave itself for a few weeks. Alas yesterday it blew again so I had to take action.

From what others have said and from a few YouTube videos Marc showed me I was fairly confident it was the old 'carbon brush dust' causing a short circuit on across the commutator.

Marc also provided the Citroen docs for the removal procedure which were also helpful if not a touch cryptic.

The first step was to remove the LDS reservoir.
The wheel arch liner on the drivers side is removed exposing the Powered Steering pump and it's feed from the LDS tank that pokes through the inner wing:



Close-Up of the Powered steering feed pipe:



After the PS pump's pipe is removed the LDS pump feed pipe can be removed. After undoing the two flanged nuts on top of the LDS tank it can be lifted clear out of the way of the pump:



After that, there is a clear view of the two high pressure pipes that supply the front and rear rigidity regulators: (shown un-done in the pics) They seemed to be between 10 and 11mm but I found an imperial spanner that fit better.

Be sure to depressurise the system with lexia first.

Rear:


Front:


After disconnecting the two visible 10mm bolts from the inside wing and removing the two 10mm nuts from the wheel-arch the pump can be lifted out (once the electrical connections are disconnected.

Pump removed:


After removing the end cap of the electric motor, the black filth is immediately visible:



Lots of conductive carbon paste everywhere:



The windings also looked dirty:



From this angle we can see the odd wear of the motor brushes, there's a lip on it. Not sure why this has happened:



Now I set about cleaning the brushes and motor housing. Using a mixture of brake cleaner and compressed air. I also filed down the lip on the motor brush so it was nice and flush:



^Much cleaner^

Final job was cleaning the inner wing and reinstalling the pump and reservoir:



After that, I added LDS and fired it up, the car rose to the normal height and didn't blow the fuse

Considerations.

I should have changed the O-rings on the high pressure suspension pipes but as this was an urgent job I didn't have time to order any in. If it starts leaking I'll replace them, it can be done with the reservoir in-situ.

On a similar vein I re-used the LDS that I drained from the tank. In an ideal world I would have put fresh in but I couldn't get hold of any today either from halfords or Eurocarparts.

Hope this helps those considering the job or who have been suffering with the maxi fuse blowing.

[GiveMeABreak]

If you look at picture No 7 ( the ‘lip’ on the motor brushes), it looks like 2 opposing ones both have a lip. Is this not intentional to keep the winding ring in place? It just seems odd that 2 opposite ones have the lip and the other 2 don’t.....

I think I’ll see if I can locate another one for comparison.

[GiveMeABreak]

The difficulty is trying to locate pictures of C5 X7 motors as these are different to earlier C5 versions. On earlier ones, you can see a white capacitor, whereas the X7 and C6 versions don’t.

So assuming the C6 version is the same as an X7, it would appear that there is no lip then Elis, so maybe they were not balanced and wore through the ends of 2 of them???

Earlier C5 Brush showing Capacitor that can fail (circled)	The later version on a C6 and possibly the X7

[EDC5]

That's a very interesting point. I think perhaps the brown plate that has the brush holders on is slightly bent; aiming two of the brushes a bit too high.

I'm not sure if the lip on the brush would cause an issue eventually but I'm certain it was the carbon dust in this case.

The commutator is held in place by the central shaft that sits in a bronze bearing on the motor cover.

[wurlycorner]

Great pics and interesting findings.

Marc are you sure the white thing is a capacitor? It looks just like a wire wound resistor.

That brush wear (with the lip) won't be by design, it's either poor manufacturing tolerances causing the brush to ride up, or poor initial assembly causing uneven wear.

With no ventilation, there is no chance for the carbon dust to be blown out and since they've probably used cheap (poor quality) Chinese carbon brushes in these later models, the dust problem will be exacerbated.

[GiveMeABreak]

Whoops, I typed 'Capacity' in the table on my last post Iain - blame it on the ipad keyboard! It is referred to as a capacitor, not a resistor that can fail on previous C5s from what I can tell.=, but there isn't any documentation that refers to the 'internals' unfortunately. But it could well be a resistor if others are confused too!

[white exec]

Looks like a high-wattage ceramic bodied resistor, possibly to limit current surge when motor starts?

[xantia_v6]

That component is fairly clearly connected across the supply leads, which would be an odd place to put a resistor. A capacitor would be much more sensible, considering the inductors in series with the brushes furthest from the input wires. The component looks rather like a polyester capacitor to me.

[white exec]

If across the supply wires, likely an R-C suppressor.
Those inductors are hefty things.

[EDC5]

It's definitely a capacitor on the pumps fitted to the earlier C5, not sure why they are omitted on the X7s.

That brush wear (with the lip) won't be by design, it's either poor manufacturing tolerances causing the brush to ride up, or poor initial assembly causing uneven wear.

With no ventilation, there is no chance for the carbon dust to be blown out and since they've probably used cheap (poor quality) Chinese carbon brushes in these later models, the dust problem will be exacerbated.

That's what I thought, I've never seen motor brushes worn like that. It's a bit late to do anything about the alignment of the brush holders now as it's all reassembled

I'm thinking the designers knew that if they ventilated the motor housing then any overflowing LDS would immediately enter the motor and cause issues, hence the 'sealed' nature of the motor casing. However, it appears that over time spilt LDS can seep in through the joins between the motor end cap and the main housing.
For this reason I considered sealing the motor up with some RTV silicone but decided against in the end. My plan is to never allow the LDS to overflow again

[white exec]

Improvise a cover for the motor, from a cut-down polythene bottle/container. That should keep any fluid out.

On the peculiar wear-step on the brushes, is it possible they started out ok, but have shortened with wear, were not kept as horizontal as they should be? Just a guess.

[GiveMeABreak]

That seems to be the case Chris, as I have looked without success, for any similar 'worn' ones. It just seemed odd that is was the 2 opposing ones that were worn.

[EDC5]

Perhaps it was a production issue as wurlycorner suggests or maybe the whole plastic assembly has got hot at some point and distorted. I feel like the brush assembly should be more rigid but it is what it is unfortunately.

I'll have a look this weekend at possible covers but as long as the LDS never overflows then there is no way for the oil to get into the motor.

[Paul-R]

It might not be LDS. Engine oil can also bung things up. And it doesn't have to be a leak. Careless topping up of either could be the culprit.

[white exec]

Could be the plastic brush baseplate having distorted.
Looking at your photo #6, it does look as if the brushes have a very loose fit vertically in their brass guides. Seems to be a sizeable gap above the brushes, and this is filled with brush debris. Or are those brass tubes lined with something, which would be unusual?
Brushes should be a decent fit in this type of motor, ie they should slide freely in their holders, without sticking and without slop.
Could incorrect brushes have been fitted, maybe at factory?
Plenty of companies specialising in motor brush stock/supply. All you need is some accurate dimensions (length not critical; can be reduced if necessary).
If slightly too tight a fit, stroking the brush on a dead flat bit of emery paper will ease it.