Citroen XM Forum

It is also worth checking that the belt driving the hydraulic pump is tight and in good condition.

Just a couple of hints with suction line:

* the hydraulic pump is usually mounted above the alternator - any leaks will drip onto the alternator, then seep inside and cause the alternator to fail.

* The suction line is the only rubber/flexible line attached to the pump.

* On the reservoir end, the suction line may not (externally) be the thickest hose, but is connected to the thickest spigot protruding from the top of the reservoir.

Mitki4a wrote: ↑

Fri Nov 20, 2020 9:20 am

Are you saying that the peeling rubber on top isn't structural and just there to keep moisture from getting in?

I did a quick peek at the struts from below and metal seems solid. To check the rubber do I have to disassemble anything, or just have it on a lift with wheels hanging?

The rubber coating on the upper side of the plate is just for corrosion protection.

To fully check the metal to rubber bond and for rubber splitting just have the wheels hanging, no need to disassemble anything.
Another check is to raise the car to the highest setting and make a mental note of the gap between the sphere and the scuttle lip.
Raising the car puts the suspension under greater pressure as all the rubber components resist twisting, which causes the strut top rubber to stretch.
Strut tops close to failure will allow the sphere to contact the scuttle lip.

From the pictures you have posted, I can see those strut tops are in very good condition and don't foresee any risk of failure.

For long term protection, remove the spheres and strut tops from the hydraulic rams, trim any peeling rubber on the upper side, clean all the metal plate with a rotary wire brush, then paint.

I forgot to answer your sunroof query.
The sunroof should automatically park at the closed position.
This is controlled by the two micro switches mounted on the drive gear. These are probably sticking due to lack of use.
Try squirting them with switch cleaner, they will probably free off with a bit of use.

For the brake lamp warning, clean the bulbs and holders and the connector onto the lamp unit, then add a secondary Gnd wire to the loom. There is an unused Gnd point just below the lamp cluster, behind the carpet.
The Gnd wire on your car currently goes all the way back to the steering column mounting frame, through three connectors.
Iirc, the Gnd wire is the wire with a black marker on the flat ribbon cable.

For your current hydraulics issue, air will stop the front of the car lifting, even though the rear will be rising appropriately.
The suction pipe is the thick, hard, rubber pipe that runs from the tank to the top of the pump.
It should have ligarex banding, with split, cotter, pins as the tightening method.
Use a small screwdriver to rotate the pin to tighten the band.
Another source of air ingress could be a split hose spigot on the reservoir. This is uncommon, but can happen.

It would be worth checking the 12mm pressure relief bolt on the regulator is tight.
This bolt faces directly forward half way up the regulator body.

If you used the height control to fully lower the car, then select maximum height, it can take a while to lift and is likely to make the low pressure warning illuminate, as the system fully evacuates of pressurised fluid, so needs to recharge. This is normal.

Pump drive belt seems to be in good order, it is pretty tight and seems to be turning well.
Both ends of the suction pipe are very solidly attached and don't move or turn at all.


I have read a lot of misconceptions about that LHM level float. In fact the orange plastic ring stays at the highest position no matter what height the suspension is. Seems like whoever has been filling it up previously thought the copper ring is the one to watch I took out the cap of the reservoir to make sure the float wasn't stuck. Indeed it does seem to be overfilled.


I took a look at the fluid before and after driving for a bit.

It seems to have a bit of a yellowish tint and is bit darker than normal.

This is after it had been sitting overnight ^

This is after driving for 10mins. Looks like there were more tiny bubbles in it.

Great detective work, and great photos!

However I haven't a clue what your first photo in your most recent post is showing. I am pretty certain it has nothing to do with the hydraulic system - it might be to do with vacuum.

The 2nd photo is definitely the reservoir - totally agree with your deductions - reservoir overfilled (no big deal unless it's actually overflowing), and fluid looking a bit old. The suction line is the fat one on the left.

Your pump should look like this:
As well as the hard/thick rubber suction line, it has two metal high pressure tubes attached. As I noted before - it is usually found above the alternator and driven by the same belt (I haven't seen the layout of your engine bay - only the petrol V6).

DownUnderXM wrote: ↑

Sat Nov 21, 2020 2:27 pm

Great detective work, and great photos!

However I haven't a clue what your first photo in your most recent post is showing. I am pretty certain it has nothing to do with the hydraulic system - it might be to do with vacuum.

The 2nd photo is definitely the reservoir - totally agree with your deductions - reservoir overfilled (no big deal unless it's actually overflowing), and fluid looking a bit old. The suction line is the fat one on the left.

Your pump should look like this:

hydraulic pump.jpg

As well as the hard/thick rubber suction line, it has two metal high pressure tubes attached. As I noted before - it is usually found above the alternator and driven by the same belt (I haven't seen the layout of your engine bay - only the petrol V6).

Sorry it does look confusing. There it is.

I should have it in for a mechanic to properly look it over next week. It is difficult to find ones, who are actually willing to take on this stuff

Please bear with my incompetence. There is this unit in front of the engine, perhaps a part of the hydraulics? A pipe going into it looks oily and is the only suspicious thing I could see.

The amount of air in the fluid does not look serious. The fluid is not too dirty, but it doesn't look like LHM at all - more like a very thin lubricating oil. It is essential that the system is run on LHM (now LHM Plus) and nothing else.

The level indicator float is a slim unit that can be removed without needing to remove the complete plastic reservoir top (known as "the octopus"). Unplug the level sensor, and rotate its rectangular horizontal plastic top (immediately under the clear dome) about 90deg anticlockwise (iirc). It can then be lifted out. Inverting it a few times will show whether the internal float/indicator is free to move, or not. The unit contains a simple switch, to flash a dash warning if the level is very low.

Re: the fluid, I think you need to get that out altogether.
Use an oil suction syringe (or some other means) to suck out as much as you can, and if you are able, remove the reservoir altogether (all fluid connections are to the octopus, none underneath) and wash it out with petrol, and refit.

Get hold of a 5-litre can of Total Hydraurincage - it's Citroen pt.no. 1135001. It is still in production by Total, but your local Citroen parts counter might have to order it in. Price varies, but usually just a bit more expensive than standard LHM. (Only Citroen sell it, except a very few classic Citroen specialists.)

Run the car on this for 1500-5000km. It behaves pretty much like normal LHM, but contains cleaning agents to remove sludge and contamination. When you first put it in, bleed the system at the four caliper bleed screws until the H'cage appears at each bleed screw, then you know it has got to all parts of the system. 5L is enough for a treatment, you won't need more. While it's in there, do a few Citrobics each week to give a workout to the struts and rear rams. You should start to feel the car loosen up before long.

After the 1500-5000km, remove it, fit a new pair of reservoir filters is a good idea, and refill with LHM. Bleed the system again until new, clean, green LHM appears at each bleed screw.

Just noticed that your Purflux fuel filter has lost its priming button, and been stoppered off with a bracket and bolt.
A replacement priming button/diaphragm is available as a spare part (any good motor factor), or you can replace the complete filter top (also available as a part) if you prefer. Looks quite a tidy bodge, though!
Google 'Purflux diesel filter' to see what it should look like.

White Exec wrote: ↑

Sat Nov 21, 2020 6:06 pm

Just noticed that your Purflux fuel filter has lost its priming button, and been stoppered off with a bracket and bolt.
A replacement priming button/diaphragm is available as a spare part (any good motor factor), or you can replace the complete filter top (also available as a part) if you prefer. Looks quite a tidy bodge, though!
Google 'Purflux diesel filter' to see what it should look like.

That engine bay picture isn't mine, I took it off the internet to show what part I was looking at.

I did try to pull out just the little dome with its plastic base, but couldn't rotate it as it has a little slot in the plastic beneath that limit its movement. I tried to pull it up first but couldn't. Will try again. When I got the whole 'octopus' out the rings started going down, hence why I think it isn't jammed.

I was assured by the previous and first owner that this is infact LHM+ and it actually still got some left in the boot. Car hadn't been driven for a while until I got it and immediately did a 450km trip back home without issues Definitely an LHM and filter change is overdue and should improve things. First 2 weeks was fine until I got the steering issue. If it is not related to air in the system, perhaps something just needs refurbishing.

The only item that can affect the steering like this is the FDV (flow distribution valve), which diverts pressurised fluid either to the suspension/brakes, or the steering system.
High pressure, low flow to the suspension/brakes, low pressure, high flow to the steering.

Your last picture shows the FDV very clearly.

It's unlikely, but possible that the FDV has a stuck, or sticky shuttle, but that seems unlikely as you seem to be suffering loss of pressure to both systems. If the main system pressure drops try turning the steering a little as that should cause the shuttles to move and may rectify the fault.

The fault still appears like air entrained in the hydrauklic fluid. Try tightening the hose clamps a little, also check the suction pipe and spigot on the LHM tank.

Have you checked the 12mm pressure reief bolt on the regulator is tight?

On another note, I noticed your car has a peugeot gear knob fitted. You can still obtain the correct one from a citroen dealer. p/n 2403 E0