Xantia Frequent Regulator Pressurisation

swiss_steve · Post by **swiss_steve** » 17 Jan 2007, 07:45

Hi All,

Can anyone help me with some tips/pointers:-

My pressure regulator is cycling about every 5 seconds (the sound is something like someone trying to pull a cork out of a bottle; a kind of whoosing noise - definitely not a clicking sound, by the way).

I changed all the spheres last weekend, with the exception of the centre rear accumulator (I did that 2 years ago when I did the last total sphere change).

I also put in a new Pleiades Hydraulic Pump three weeks ago (the steering was not getting enough fluid and was sometimes erratic - that's solved that problem).

With the brand new main accumulator on the regulator, I thought I would solve the regulator cycling problem - but it's still there.

So does it sound like my regulator itself is also due for change, or something else I should consider? Present milage circa 160k miles, 1997, 1.9TD.

Incidentally, when I changed all the spheres last weekend, I set the car on high, turned the engine off, then set it to low and it let itself (the car) down. Now, one week later, it only does that occasionally (when it feels like it

). It doesn't seem to matter whether the car is warm or cold - does this have any significance?

Cheers,

Steve

jeremy · Post by **jeremy** » 17 Jan 2007, 08:53

Initially I'd say the rapid cycling is due to accumulator failure. Its not unknown for a new or recharged sphere to leak.

The accumulator holds high pressure LHM. In the chamber there are 3 exits - onward to the safety valve and the rest of the system as intended, down the centre valve (rod visible in the centre) and back the way it came through the non-return ball valve.

This latter valve is a simple ball bearing forced into and off its seating by the flow pressure. Eventually the seat gets a bit ragged and it leaks - and can be re-seated by a SINGLE smart tap onto its seat using a BRASS punch.

On some cars this can be done in situ - remove accumulator, remove plate visible and catch ball bearing ( your eye is probably where it'll land). Stick ball bearing back in its hole with a dab of grease and strike smartly with a brass punch. Brass is essential as steel may put a flat on the ball - and only strike it once - you want a single seat not multiple overlapping ones!)

Re-assemble.

My BX went from 9 seconds to so slow I can't be bothered to measure it. Others report significant improvements - and its free!

Not sure what is going on with your suspension - shouldn't it drop when you select low? - sorry I'm a BX man and confused by this modern technology.

swiss_steve · Post by **swiss_steve** » 17 Jan 2007, 09:16

Hi Jeremy,

Yes, if it wasn't for the new accumulator sphere, I would have also immediately thought that the sphere was the problem, but I am quite confident of the general quality of the Pleiades spheres as all the new suspension ones have now given my wonderful comfortable ride back.

Like you, I'm coming round to thinking that its the accumulator regulator. I'll ry to get hold of a stethoscope to see if the cycling noise comes from this component.

I will certainly try to 're-seat' the ball bearing, when I can find or come across a brass punch - any idea how large the punch diameter should be? I assume that the head of the punch must be flat.....

I believe my Xantia has a non-return valve in the suspension system that stops it settling after you switch off the engine (unlike my old XM from years ago). However, I did try the old 'sit in the boot after switching off the engine' trick, but it didn't rise back up - yet the ride height is fine (so no problem with the height correctors there).

Seems to all point to the acc. regulator and perhaps that sticking ball bearing, doesn't it?...

jeremy · Post by **jeremy** » 17 Jan 2007, 09:27

I think the non-return ball valve is 6mm. For the first one I did I didn't have a brass punch handy - so I used an old MIG welder copper nozzle held on to the end of a steel punch with an old 4.5mm Citroen pipe seal (as a convenient bit of tube!) A flat or slightly dished end would be fine - its not critical.

Your car will have anti-sink - which is a high quality valve inserted in the suspension circuits to prevent the suspension dropping when the car is left. The sphere is to replace pressure in the rear brake - suspension circuit which can be suddenly released when the thing is started. This problem is worse on these cars as they have a 2 outlet pump - 6 for the steering, 2 for the suspension - so there isn't much power for the brakes and suspension - which means the accumulator is very important.

The sit in the boot test still works on cars with anti-sink.

There is an excellent Technical Guide on the Citroen DIY site - follow links to 'Technical Guide' at top left.

http://www.tramontana.co.hu/citroen/

steelcityuk · Post by **steelcityuk** » 17 Jan 2007, 10:13

I'm chasing a similar faulty, my regulator cycle time is 6 seconds. I reseated the non return ball valve using a brass bolt. I think my short cycle time is due to leakage somewhere in the rear suspension or brake valve.

Steve.

jeremy · Post by **jeremy** » 17 Jan 2007, 14:30

Could be - you may be able to find it by checking the return pipes and seeing where the flow comes from.

Worth a search - there have been some other postings on this subject.

steelcityuk · Post by **steelcityuk** » 17 Jan 2007, 15:59

I'm on a bit of a go slow at the moment with the car. Waiting for better weather, more time and some used spares I'm in the process of buying -

Front height sensor unit
Front HA block and valve (with sphere)
ABS unit
Hydraulic pump
Regulator unit - no sphere
Suspension height adjuster
ABS computer
ECU and suspension computer

Offered the lot plus a few other bits and bats for £65!

Steve.

slim123 · Post by **slim123** » 17 Jan 2007, 17:56

Hi Steve.

From experience, the re-seating of the ball very seldom works, I am told that this is probabaly due to the fact that the seat is hardened! I guess that if a small piece of seal rubber was trapped behind it then smacking it with a drift may help, but if the seat is worn then you aint gonna achive much.

But hey, give it a go, it costs nothing and it is very quick to do, if it dont work then you have lost nothing.

I rekon that the problem will be the regulator itself, these are getting to be more and more of a common failure these days. In the days of the DS, GS/A and CX the regulator used to go on forever, but I guess that quality went down hill.

Do you have a good business relationship with the Pleiades boys, personaly I find them very helpfull, they can test these things for you if you need to, otherwise its a game of take a guess and change it.

Regards
Slim

swiss_steve · Post by **swiss_steve** » 18 Jan 2007, 07:27

Hi Slim,

Thanks for the advice.

I really don't have too much time to waste on trying various 'fixes' if there's a minimal chance it will succeed - I have a very busy life these days! If there's an odds on chance that re-seating the ball bearing won't work, I'd rather cut my losses and just change the unit.

But I do get on well with the Pleiades boys (I must be visiting them every month or so these days buying more and more parts as I gradually renew all the hydraulic bits on my car!). My other problem is that I really rely on my car for my daily business and cannot afford to have it off the road whilst the testing of any parts takes place - it's just easier & quicker with a known result if I just change the part. They only cost GBP65 + VAT from Pleiades....

Cheers,

Steve

uhn113x · Post by **uhn113x** » 18 Jan 2007, 08:20

slim123 wrote:Hi Steve.

From experience, the re-seating of the ball very seldom works, I am told that this is probabaly due to the fact that the seat is hardened! I guess that if a small piece of seal rubber was trapped behind it then smacking it with a drift may help, but if the seat is worn then you aint gonna achive much.

I'm not doubting what you are saying, Slim, but I would be surprised if the seating is hardened - it is just a drilling in the mild steel regulator body. Unless later ones have an insert?

The only way for Cit to harden it would be to case-harden the whole thing. Also there would be no need, as the steel ball is glass-hard.

Any bits of rubber stuck in the hole would not stay there very long with the rush of LHM through it when the PR cuts in.

I have known a tap on the seating to cure the problem every time when there was no audible click because the seat was worn.

JMO

jeremy · Post by **jeremy** » 18 Jan 2007, 11:20

I think the seat for the non-return valve is unlikely to be hardened - as it seems to be a simple drilling in the body which is presumably a malleable casting. On the one I looked at off the car there was no sign of a colour change round the hole - and its difficult to see how it could be hardened unless an insert was used - which would of course be visible.

In the good old Laycock overdrive a similar system of valves is used but on that at least one of the valve seats is simply a drilling in the aluminum body.

slim123 · Post by **slim123** » 18 Jan 2007, 20:40

Off an old regulator that was causing this problem, I removed the ball and selected the appropriate sized drill bit and decided to try and "clean the seat" The drill bit would not touch it!!! conclusion, it's hard.

Regards
Slim

uhn113x · Post by **uhn113x** » 19 Jan 2007, 07:29

That is interesting!

Wonder if it was just work-hardened? This can happen with steel (and other metals).

The ball is fetched a violent whack every time cutout occurs, hence the loud click. Has it been work-hardened by that?

Cannot see how it could have been hardened originally; there may be a way. Are some regulators different in that respect?

I have sometimes drilled or turned mild steel and when the drill or tool has become blunt, you get a hard skin that is difficult to cut. Maybe this is the reason?