Exclusive 2.0 Hdi: no clicks from regulator

[Edhertz]

Hello folks I’m writing to ask if some one can help me identify the return lines on the LHM reservoir. Background: after starting engine from cold red suspension light remains on for approx 40 seconds, then rear and front end rises slowly to normal position. I can hear no ticks from the regulator in any of the suspension positions (one can be heard occasionally front and rear). Suspension works in all positions but takes an age to rise from low. I am guessing a poorly performing pump or seal/s somewhere. Hydra flush carried out last year and all filters cleaned with fresh charge of LHM. I’ve checked the LHM return lines and found the following numbered from left in pic: 1; no fluid, 2; full bore high rate, 3; reasonably high guess ½ pint /min, 4; few drips, 6; dry,7;dry. I guess 2 is the main return line from the regulator? If this is the case can I expect it to shut off when rising from low to high position? Steering /brakes fine. There's are a lot here so thanks in advance.

[Old-Guy]

The red STOP light is triggered by all sorts of things, not just low hydraulic pressure.
If you follow line 2 back down the side of the reservoir, you will find that it's the common end of a manifold with 4+ lines into it. These are returns from all sorts of places.

then rear and front end rises slowly to normal position.

Are you saying that your car sinks to low when left? It shouldn't unless the car is loaded and unloaded several times before the engine is restarted. A Xantia (even when not used for days) should sink when the occupants get in and then, even if the car isn't started, rise back to normal height within 20-25 seconds because the (front) accumulator and rear (anti-sink) sphere should still hold enough reserve pressure to maintain more or less normal height. The rear anti-sink valve is crucial to ensuring that the anti-sink valve closes and stays closed. However, if you use the brakes before the pump has re-pressurised the accumulator, it takes longer to do so.

Basic test of the spheres: after leaving the car for some hours, sit on the tailgate/hatch sill. The car should sink by several inches equally on both sides (rear suspension spheres OK); after about 20 seconds, the rear should rise back to the original position ('anti-sink' sphere OK). Repeat for the front though due to the greater 'spring stiffness' of the front spheres the front end won't sink as much as the rear. If you suspect a corner sphere, once the hydraulics are up to pressure, push down hard on the suspect corner; it should bounce easily. If it's hard(ish), and the ride height is normal, the sphere needs replacing.

A crucial question is "When were the spheres last changed?" Sphere life depends on time, mileage, how heavily the car is usually loaded and what sort of roads it used on. After 11 years and 67,000 miles of gentle use by the original owner, the original spheres on my estate were nearing the end of their lives but that seems to be exceptional. 5 years and 42,000 rather harder miles later, the rear suspension spheres seem to be getting a bit tired (the ride isn't what it was with new spheres). Opinion varies, but 5 years/50,000 is often suggested as reasonable life expectation. Spheres are expensive from Citroen, but about £25 each from a specialist like GSF. Replacing spheres is not at all difficult provided the correct procedure is followed.

[VertVega]

A very short answer would be: At least accumulator needs to be replaced (sphere in front, middle).

[Edhertz]

Thanks for replies. The position so far: All front spheres replaced 18months ago, rear anti sink and accumulator replaced today. Suspension front and back smooth,free and responsive. Run engine, suspension in normal postion for a while, stop engine, wait 1hour, sit on tail gate, car does not move up or down, same with front. Start engine, low pressure light on for a few seconds, rear rises, front rises. Rear suspension not stationary ie; moves up, dwells and drops 3 inches or so and rises again continiously. No clicks.

[xantia_v6]

The oscillating rear end is likely to be a partially seized rear height corrector.
Try pulling the hydraoactive fuse (f8 in the engine compartment) and see if you get ticks.

[Chris570]

my thoughts on this are either flat acc sphere (but usualy that will put the light out instantly when starting as it won't be able to build a reserve of pressure before pressurising the security valve (which is where the pressure sensor is) or your regulator is weak which would explain the slow to rise and the slow to extinguish light. when rising from low to high does the suspension move slowly or in stages? you could also of course have a high internal leakage but this is unlikely given the tests you've done.

just as an FYI the anti sink sphere on the back is actually a rear brake accumulator and T's into the feed line to the doseur valve. when the system pressure is low (engine off front ACC exhausted) the anti sink valve will close and this leaves the "anti-sink sphere" on the closed side of the suspension so that sphere has nothing at all to do with height correction. Another useful bit of info is that if any of the suspension spheres are low that can actually cause the car to sink when left as they provide the pressure balanace on their side of the suspension (if they are weaker than the Acc sphere they pressure difference won't be enough to close the anti-sink valve. The rear brake accumulator though shouldn't be overlooked as in the event of a hydraulicv pressure loss (engine failure, broken belt etc) it is the only thing to provide braking effort for the rear.

Also, do xantia v6's suggestion

[Edhertz]

Thanks for your thoughts. Pulled F8 ..... no clicks. Will have a look at rear height corrector as suggested. Point re accumulator spheres, all renewed so was hoping I could eliminate that side together with anti sinks. Could it be that one of the regulator valves is not holding at shut off hence loss of accumulator pressure? I would like to think that I do not need to replace the pump. Could it be that the absence of clicks suggests a mechanical malfunction within the regulator or insufficient pressure to get the relief to activate? Is it normal to have full bore to No2 reservoir return with no interruption in flow from high to low position?

[CitroJim]

It may be a weak pump or a duff pressure regulator. A weak pump may not be able to reach the cut-out pressure of the regulator or the regulator may be in a permanent state of cut-out.

Only way to be sure is to measure the mainline pressure out of the regulator using a tee-gauge like this:



A good pump and pressure regulator combination will show 170 bars on the gauge just before cut-out (and a click) and drop to around 145 bars before you it cuts in again. If your pump is weak and it never manages 170 bars such a test will show it clearly...

[Edhertz]

Sorry it's a bit late ( went off the radar) but thanks for replies. Still have problem but learning to live with it.

[lurchy666]

i replaced acc and ant sink on my estate hdi a few months back i dont get a click but i do get what sound like a sieres of clicks usualy 3-4 within about a second if im doing citarobics or starting up from cold while the suspension is sorting itself out cause it always sinks a bit over night, it sounds quite wierd, mine wont do the leave it for a few hours and sit on the boot and raise you back up thing either, if you do it as soon as you stop the engine it'll do it but give it 10-15 minutes it wont do it, now on mine there are only 2 spheres i havent done yet, the back 2 on my estate look like bloody cannon balls, god only knows when they was last changed but they seem ok to me suspension wise,