Stupid question time

[larkspeed]

1998 Xantia 18.i 5 Door Hatchback

I recently changed both front spheres and the accumulator.

Car now rides really nice but I have a silly question.

After running the engine for a bit and moving the suspension up and down a few times and then turning the engine off.

If I then loosen the bleed bolt on the accumulator should I hear any air hissing out at all or is it normal for there always to be a bit.

When I open it I hear air escaping and then what sounds like a valve closing and the air stops.

I have noticed that after I shut the engine off the car seems to drop a bit on the front and then rise back up and it seems to me like the front end seems to ride a little high when driving.

Could air in the system be causing this.

And what is the correct bleeding procedure for the suspension?

[Hell Razor5543]

Did you bleed all the brakes after swapping the spheres?

There is an awful lot of pressure in the system (at least 170bar), and this will make a whistling noise when you turn the pressure release bolt even if there isn't any air in the system. The following link covers everything hydro-pneumatic related, including bleeding the brakes;

http://www.frenchcarforum.co.uk/forum/v ... 22&t=24595" onclick="window.open(this.href);return false;

By the way, there isn't (to my mind, at least) any stupid questions, just stupid (avoidable) mistakes. You ask questions to avoid the mistakes.

[larkspeed]

ok well it's that whistling noise I can hear then and not air as such.

Running it depressurized with the bolt open does not produce any foam at the tank either.

No I didn't bleed the brakes as they did not need it, they work just as good as they always did.

Actually someone on this forum told me that bleeding of the brakes is not needed when just changing spheres unless they react different.

[Hell Razor5543]

I would still bleed the brakes. While the steering and suspension circulate, and the fluid gets back to the reservoir (including any air in those systems), the brakes are dead ends, and if any air gets there it stays there. As the accumulator sphere feeds the suspension and brakes it is possible that you may now have air in the braking system. I always bleed the brakes whenever I work on the hydro pneumatic system (just to be sure).

[citronut]

there is no need to bleed the brakes after fitting spheres, except for the possibility gas had entered the system from the old spheres loosing there gas,

that said it dosent hurt to give the brakes a bleed from time to time,

citroen used to state for bleeding the system after opening the hydraulic circuit, with the engine idling open the bleed valve, let it continue idling for around 2 minutes, then hold the revs at 2.5k rpm whilst closing the bleed valve,

[larkspeed]

That's exactly what I did.

like I say the brakes work just like they are supposed to, my concern was just what sounded like air but that has been explained.

I'm new to these types of suspension systems so will end up asking loads of questions.

Probably in about 3 months as funds allow i'll change the rear spheres and anti sink as well, they are working fine but since I have no idea how long they have been on i'll change them to be sure they don't fail when I'm pulling my caravan or something.

I'll also be changing the brake pads soon and i'll bleed the system then.

[foeism]

there is no need to bleed the brakes after fitting spheres, except for the possibility gas had entered the system from the old spheres loosing there gas,

that said it dosent hurt to give the brakes a bleed from time to time,

citroen used to state for bleeding the system after opening the hydraulic circuit, with the engine idling open the bleed valve, let it continue idling for around 2 minutes, then hold the revs at 2.5k rpm whilst closing the bleed valve,

My apologies for hijacking, but when i undid the bleed there was no hissing, and I did up the bleed nut without holding the revs at 2.5k

Do I need to do the b=above procedure?

[citronut]

My apologies for hijacking,

this is one of the criteria of using the FCF, its in the rule book along with

but when i undid the bleed there was no hissing, and I did up the bleed nut without holding the revs at 2.5k

Do I need to do the b=above procedure?

you dont always hear air escaping but it wont hurt to run it again as i said/citroen used to state as above

[foeism]

My apologies for hijacking,

this is one of the criteria of using the FCF, its in the rule book along with

but when i undid the bleed there was no hissing, and I did up the bleed nut without holding the revs at 2.5k

Do I need to do the b=above procedure?

you dont always hear air escaping but it wont hurt to run it again as i said/citroen used to state as above

Hahaha! excellent reply thanks I will not do this again.

[fangorn]

there is no need to bleed the brakes after fitting spheres, except for the possibility gas had entered the system from the old spheres loosing there gas,

that said it dosent hurt to give the brakes a bleed from time to time,

citroen used to state for bleeding the system after opening the hydraulic circuit, with the engine idling open the bleed valve, let it continue idling for around 2 minutes, then hold the revs at 2.5k rpm whilst closing the bleed valve

Glad I found just THE answer I was looking for
As larkspeed I am going to change accumulator and front spheres now and the rest spheres later when I have money and just wondered too, is it necessary to bleed the system afterwards.

Thanks !!

[Hell Razor5543]

I always bleed the brakes whenever I work on the hydro pneumatics. While the suspension and steering are circulatory systems, the brakes are not, and any air that gets caught in them could cause braking issues.

[Xantidote]

I've only ever found a bit of air (presumably nitrogen) in the rear brake calipers, and I bleed the rears about once a year, basically when a wheel's been removed which makes access easy. Never found air in the front calipers.

[fangorn]

Thanks a lot for your answers, this is the best Citroen forum in the whole wide world
Yeah, I do plan to bleed the system a bit later just to make sure and because it's so easy procedure with these lovely cars. The reason I asked is that I must work under the big blue sky and it's autumn now and the weather is a bit nasty right now,,, I just thought to change the spheres now and if possible drive the car untill in a couple of weeks I can borrow a nice, warm carage (with a roof, of course) and complete the job then

[larkspeed]

Well it's been 2 weeks since I changed the fronts and the accumulator without bleeding the brakes and I have had no braking issues at all.

[fangorn]

OK, then I might also skip the bleeding procedure this time since only a couple of months ago I changed the LHM, flushed the system carefully and bleeded it.