Bleeding Air

[DocBrown]

What is the correct procedure for purging trapped air from a Xantia's hydropneumatic system?

My 1997 1.9 TD SX is in good condition and has new spheres front and rear, new droplinks, rod ends and balljoints but the car 'shrugs' or wallows from side to side when going over small road bumps/irregularities etc.

 

I have been advised on this forum that there may be trapped air in the system although I did bleed the brakes after sphere replacement just in case.

Is there a better way of purging trapped air as currently, the ride quality is no better than a conventionally sprung car in fact my brothers 406 estate drives a lot smoother as well.

Any advice please would be great thanks. :unsure:

[techbod]

there is a bleed screw on the front of the regulator, raise the car to full height then lowest then turn the bleed screw a couple of threads you should hear the are coming out and repeat a few times ( ensure the rear end goes all the way down every time ) I normally sit on the boot lip till its all the way down and it took several times and did it a few days later to ensure all the air was out

[DocBrown]

there is a bleed screw on the front of the regulator, raise the car to full height then lowest then turn the bleed screw a couple of threads you should hear the are coming out and repeat a few times ( ensure the rear end goes all the way down every time ) I normally sit on the boot lip till its all the way down and it took several times and did it a few days later to ensure all the air was out

 

Thanks for replying.

I have used the bleed screw on the regulator but thought that it only released the hydraulic pressure to enable sphere removal. Come to mention it, when I last depressurised the system to swap rear spheres, I didn't hear whistling sound or air but the LHM pressure was released. Maybe it needs a dose of hydraflush just in case the ball bearing under the bleed screw is stuck?

 

Anyway, I will go and carry out some citroen aerobics and hopefully get back the 'magic carpet' ride.

Cheers

Andrew

[techbod]

if the ride height was well down when you replaced the spheres then I don't see a problem? the pressure was released ! otherwise it would have exploded in your face and took your head off, to replace a sphere place a trolley jack under the jacking point then drop the suspension to the lowest point then jack it up with the bleed screw open this deletes the pressure in the system, to change a sphere when it pumped up and the release pressure bold is locked on holds pressure on the rear via the anti sink valve/sphere so when new spheres are fitted they don't work properly because air is locked in the system between the anti sink valve and the suspension spheres and needs to be bled many times to get all the air out

[Guest Peter Mann]

The standard Xantia suspension does not incorporate the fabled cloud ride. I think that Citroen firmed and flattened the ride in an attempt to woo the driver of conventional cars ; certainly, it took me a long time to fully come to terms with the transition from my informative 404 Peuget to the inscrutable DS, and it would have been all too easy to be dismissive of a car that responded so differently to the controls and had such a disconcertingly different feel.

An hydractive suspension is quite a different prospect, in that the compliance over uneven ground is astonishingly flexible, but firms in the instant that swerving or braking begins.

The defining question with the Citroen is whether the car tracks true to the steering over big bumps and changes of camber ; this requires an eye for how consistently it follows the curve, which is quite different from the motion of the body as it traverses the terrain. Failure to track an arc with precision would indicate a serious problem. The technique is to make no sudden adjustments during the course of the corner, because that will lead to disconcerting behaviour.

Air in the suspension should be vented into the reservoir by Citroebics, or even just in the course of daily life. If there were some air entrained, it would tend to manifest as excessive motion with an under-damped character.

[techbod]

hmmm interesting answer "if any of that was true" yes the later xantias are not as smooth as the older BX but its still much better than standard springs and as for Citroebics it would be nice if it did automatically bleed its self but it doesn't and that's a fact air getting locked in a high place like the rear end is a pig to get out ;) don't compare a pug 404 to a Citroen please the difference is vast even though they use the same engine but thats where I draw the line ;)

[DocBrown]

if the ride height was well down when you replaced the spheres then I don't see a problem? the pressure was released ! otherwise it would have exploded in your face and took your head off, to replace a sphere place a trolley jack under the jacking point then drop the suspension to the lowest point then jack it up with the bleed screw open this deletes the pressure in the system, to change a sphere when it pumped up and the release pressure bold is locked on holds pressure on the rear via the anti sink valve/sphere so when new spheres are fitted they don't work properly because air is locked in the system between the anti sink valve and the suspension spheres and needs to be bled many times to get all the air out

Yes, I did change the spheres with suspension on lowest setting as I once witnessed a mechanic undo a sphere when it was pressurised.

I disagree about the Xantia not having the fabled magic carpet ride. I recently drove a colleagues M reg 1.9 TD and the ride quality was amazing. After that I realised my 1997 1.9 TD has 'issues' I realise it won't match the ride quality of a DS or CX but this friends Xantia was almost as good and lightyears ahead of my car. I will try another dose of raising and lowering plus I will bleed the rear brakes again as these are linked to rear suspension. I will let you know the results.

Cheers

Doc

[techbod]

when bleeding the breaks there is a good tip ( get a clear pipe that runs from the calipers to the top up tank ) fish tank pipes work well and its cheap for a lot it saves running back and forth keeping an eye on the level ;)

[Guest Peter Mann]

When bleeding the brakes on an hydropneumatic Citroen, it is easiest done by applying force to the brake pedal with a piece of timber against the driver's seat ... and the engine running.

Under these conditions, releasing the bleed nipple will vent the line and brake cylinder of air and stale fluid, and it can be shut off as soon as clean oil comes through (the oil trapped in the brake cylinder gradually darkens with contaminants).

This technique allows continous monitoring of the discharge, and the amount of clean fluid discarded is trivial. A short piece of transparent tube fitted over the discharge nipple prevents risk of contaminating the brake assembly with oil, and allows the discharged fluid to be captured for examination and disposal.

[techbod]

due to a nasty arrogant pm I got from the above ^ even though I was chuckled to death reading it :D and nothing personal taken by any means " I understand where your coming from " so if the chap doesn't sort it his reward is a pug 404 ( which is a nice motor by the way ) and if he solves it then he keeps his pride and joy :) ;) this is no personal attack by any means ;)

[techbod]

ahhhh you changed your 404 for a DS what a smart move there and a money maker ;)

[techbod]

http://uk.youtube.com/watch?v=eO94Wbz-A3k&...feature=related