Xantia residual brake pressure,(engine off), insufficient.

[budgie75]

I'm a failure, help me!
MOT Failure Xantia Estate 1900 TD 1996 220,000 Miles

The failure note reads
: Brake pedal has insufficient assistance [3.3.D.3b]for at least two more brake applications after the warning device has operated.
Some observations that may or may not be relevant are:
1. Ticking of regulator is every 7 seconds
2. For the first 30 seconds after start up there is a disgraceful ammouint of chattering from the hydraulic pump.
3. I have recently replaced all spheres EXCEPT THE ONE ON THE REGULATOR, but I think it has only done around 20,00 miles.
4. The pump has done 44,000 miles.
5. When bleeding the rear brakes following some pipe work back there I had difficulty getting any fluid at all to come out of the bleed nipple. I had to jack up the rear suspension arms (to simulate a rear load) to achieve this.
Would appreciate any suggestions. Got a retest next Wednesday!

[AndersDK]

1. Ticking of regulator is every 7 seconds

The first symptom to persuade on a hydraulic Citroen
Replace that acc sphere on the regulator. Be SURE to get a brand new sphere. No recon or regas or second hand (phew !)

2. For the first 30 seconds after start up there is a disgraceful ammouint of chattering from the hydraulic pump.

Sounds pretty normal. Might in fact be the regulator and not the pump you can hear.

3. I have recently replaced all spheres EXCEPT THE ONE ON THE REGULATOR, but I think it has only done around 20,00 miles.
4. The pump has done 44,000 miles.

As above. The acc sphere is most important. Always to be replaced by new one. Pump good as new on 44Kmiles - unlikely to be at fault.

5. When bleeding the rear brakes following some pipe work back there I had difficulty getting any fluid at all to come out of the bleed nipple. I had to jack up the rear suspension arms (to simulate a rear load) to achieve this.

Absolutely normal. Next time doing this job simply set suspension to highest. Then rear suspension would be fed with max pressure - which again is fed to the rear brakes.
Lame Q I know : the brake pedal was in fact depressed during bleeding ? - and engine idling ?

[budgie75]

To AndersDK
Thanks for your fast response
Not sure if I'm using this forum correctly, bit of a virgin to them.
Yes, peddle was held on + engine idling.
Another observation I left if out last time : when I was taking off a rear sphere I got properly showered with the green stuff even though I had observed the correct procedure.
A week later I decided to change the 'anti-sink' sphere so was extra careful of procedure, but same again, pressure still there. AND SHE IS VERY RELUCTANT TO SINK, when playing up and down games and I wondered if all this points to a sticky valve at the back?

As to my immediate problems, I shall get a new accumulator sphere pronto and see what that does.

Cheers

[mezuk04]

Just realized i have driven all the home with the height setting on the one above normal ride height

[AndersDK]

If you get a mad tomcat spraying when removing a sphere - its always because of remaining system pressure.

With antisink you can only lower de-pressurise the system with main pressure present - meaning engine (and then pump) running.
Doing it this way it should be pretty much like a standard hydraulic system - not much extra delay to lower suspension.

It may be worth running a hydracleanse cure. If that has already been done recently the HC linkage is to be suspected - and then the a/s valve

[Mandrake]

To AndersDK
Thanks for your fast response
Not sure if I'm using this forum correctly, bit of a virgin to them.
Yes, peddle was held on + engine idling.

The most reliable way to bleed the rear brakes is to make sure you only lift ONE rear wheel off the ground at a time, in addition to setting the suspension height to full. This will GUARENTEE that there is rear suspension pressure there to operate the rear brakes.

EG, lift the suspension fully up, then jack up the rear corner on one side, remove that wheel and bleed that brake alone while the opposite wheel is still resting on the ground carrying some weight. Then refit the wheel and repeat on the other side.

Little known fact: even with the height lever set to maximum, if both rear suspension arms are hanging down freely due to the entire back of the car being jacked up, there still may be no rear suspension pressure ! (due to slight misadjustment of height corrector linkages...)

Another observation I left if out last time : when I was taking off a rear sphere I got properly showered with the green stuff even though I had observed the correct procedure.
A week later I decided to change the 'anti-sink' sphere so was extra careful of procedure, but same again, pressure still there. AND SHE IS VERY RELUCTANT TO SINK, when playing up and down games and I wondered if all this points to a sticky valve at the back?

It is more likely due to you not being familiar enough with how to properly depressurize an anti-sink model. It can take quite a long time (minutes) to fully depressurize.

Basically the regulator bleed screw MUST be closed, and the engine MUST be running when you set the height lever to right down, furthermore, you should leave the engine running and the bleed screw closed for about THREE minutes before the suspension will be depressurized enough for sphere removal. This is particularly so for a Hydractive 2 model.

Before turning off the engine, try grasping one of the rear corner suspension spheres and wiggling - the entire cylinder and sphere assembly should wiggle from side to side about 1cm, if it does, you can be sure there is no pressure left. If it wont, try waiting a bit longer.

Finally now you can open the regulator bleed screw and switch off the engine.

Of course this doesn't prove that the front suspension is depressurized fully, but when the system is working normally they take approximately the same time.

Also there is a small possibility of the manual height lever being out of adjustment which could cause it not to fully depressurize, so if you still have problems with showers of oil after the above procedure you might need to check that adjustment.

Edit: Just reread your message again, are you saying that when you set the height lever right down or right up the rear doesn't respond properly ? If you set the lever down, it should start dropping in about 5 seconds or so (maximum 10 seconds) and should be visibly right down (but still have pressure in it) in about another 10-15 seconds. Is this not the case ? (But remember that the engine must be running for the car to go DOWN as well as up, on an anti-sink model)

Regards,
Simon

[jeremy]

A nearly flat sphere can cause a spray of LHM when its removed - there's not enough pressure to force the LHM down the return pipework but enough to spray it all over you.

[budgie75]

Thanks to everybody for their help. I will report back when job done.

[citronut]

as Jeremy said an almost flat or fully flat susp sphere almost certainly will give you a jet of citro blood to reach possibly 20feet or so after it has been removed,also i have never had any probs bleeding rear brakes on any hydraulic cit,by always having rear completly of the ground but firstly setting susp fully up on high,dose your brake pedle patter under your foot when braking,if so the prob you are having is air/gas still in the system,REMEMBER ALWAYS KEEP IT SIMPLE BEFORE YOU GAT ALL COMPLICATED
REGARDS MALCOLM