Xantia pressure regulator

[lux]

So, i am fiddling a bit with my X2 Xantia (changed the LHM, engine oil, replaced fuel and air filter...), but am wondering about one thing:
I watched plenty of youtube videos, and one thing that is happening in all of them, but not on my car, is the fact that when the pressure relief nut on the pressure regulator is undone, there is a sound of air coming out.

Am thinking about changing the spheres next, but would like to understand this issue before.

Kind regards

[admiral51]

Hi
I had the same issue on my last Xantia and it never caused me any problems when changing spheres, in fact i changed all of them including the Accumulator sphere.
All i did was set it to low wait a few minutes and loosen the screw. Cannot remember if it makes any difference with engine running or not but sure some real experts can help out.
There is sticky thread about changing spheres and the LHM need to try and remember where it is.
**Edit**
The link for the Spheres/LHM/Brake Bleeding

Colin

[CitroJim]

As you say Colin, and just like you, in all the years I ran Xantias I rarely depressurised using the bleed screw when swapping spheres.

In fact, if you ran a V6 Xantia the bleed screw is pretty much inaccessible anyway...

The system is, essentially, self-bleeding but with one and a bit exceptions... The rear brake lines and to a lesser extent the fronts. They're on dead-ends. If you swap rear spheres or change LHM it's a good idea to give them a good bleed. You'll only get LHM to flow out of the bleed nipples if the rear suspension is under some load... It's impossible to bleed them with the rear wheels in the air... The rear brake lines are long so bleed out at least half a pint of LHM or more... The first few mL may be horrid so carry on bleeding until nice, fresh LHM comes through...

The front brakes are on (much shorter) dead-ends too and benefit from a bleed, especially after an LHM change to flush out any old manky LHM still in them...

[CitroJim]

There is sticky thread about changing spheres and the LHM need to try and remember where it is.
**Edit**
The link for the Spheres/LHM/Brake Bleeding

Thanks for doing that Colin I was just about to go and do the same

[lux]

Read that article a couple of times, it is bookmarked and will be reffered to in the future, was just curious about the silent pressure regulator.

[Armidillo]

Yes it's normal to get a little 'whoosh' noise when you undo the pressure relief valve, but it's not air escaping - it's the sound of high pressure LHM being allowed to escape back to the reservoir.

It's not a very loud noise, and doesn't last long, so I doubt that you'd hear it if the engine was running.

[Stickyfinger]

Yes it's normal to get a little 'whoosh' noise when you undo the pressure relief valve, but it's not air escaping - it's the sound of high pressure LHM being allowed to escape back to the reservoir.

It's not a very loud noise, and doesn't last long, so I doubt that you'd hear it if the engine was running.

I hear nothing...

The V6 is pressure release screw easy to reach from under the car (stretched out arm...NOT your head !)

[aerodynamica]

Yea I think the amount of noise you get from the pressure regulator bleed bolt varies depending on what car it is. The one in my 1968 ID19B was really loud and was almost like a whistle sound!

That said, if the main accumulator sphere is completely flat then you don't get any sound because there's no stored pressure to release!