New spheres- LHM level queries.

Gaskin · Post by **Gaskin** » 16 Feb 2004, 23:56

I've just changed the front suspension and accumulator spheres on my Xantia. Thanks to all those who gave encouragement earlier. Easy peasy with jubilee clip tool('[:D]')(even easier if I hadn't tried to save time by not dropping the plastic under tray first). Anyway checked the LHM level expecting it to have dropped due to new spheres needing filling and slight fluid spillage, but not so! Now the indicator float is sitting at the top even at high setting. Citaerobics have not cured this. Having a look in the resevoir at high the fluid level seems to be 10-15cm below the top and rises ~6cm at low.
So.... would you expect the fluid level to rise if dodgy spheres were replaced? Does it sound like the level float is stuck, if so how to fix it? Any suggestions as to where the fluid level should be at high and low?
Thanks in advance.
Cheers
Duncan

Post by **philhoward** » 17 Feb 2004, 00:05

I'd reckon your float is stuck, personally...give it a sharp tap when in high and see if it falls to the bottom. Mine has a sticky float; just tap it to check!
At high, the yellow cone should be between the two rings on the sight glass... The figures you give indicate it's nearly empty on high!

alexx · Post by **alexx** » 17 Feb 2004, 00:26

LHM level SHOULD rise after refilling the spheres. Expect 0.1-0.2 dl per sphere (depending how flat it was), minus spilled quantity

Post by **philhoward** » 17 Feb 2004, 00:30

Despite the old spheres could have contained (if flat) 400/450 or 500cc of fluid each???

alexx · Post by **alexx** » 17 Feb 2004, 03:46

Let's see - nonhydractive Xantia estate '97:
central sphere, 400 ccm, compressed from 62 to 170 bar - nitrogen will be compressed to 146 ccm
front spheres, 450 ccm, 50 -> 170 bar .... to 132 ccm
rear spheres, 400 ccm, 40 -> 170 bar ... to 94 ccm
anti-sink sphere, 400 ccm, 50 -> 170 bar ... to 118 ccm
If spheres were totally flat, this volume would have been taken by LHM. After sphere replacement, there will be 716 ccm 'more' LHM, minus spilled quantity. Difference between marks is about 400 ccm.

ScottFromNZ · Post by **ScottFromNZ** » 17 Feb 2004, 09:39

My LHM level rose a little bit when the new accumulator sphere was fitted even though a bit of LHM leaked out.

Kowalski · Post by **Kowalski** » 17 Feb 2004, 14:30

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by alexx</i>

Let's see - nonhydractive Xantia estate '97:
central sphere, 400 ccm, compressed from 62 to 170 bar - nitrogen will be compressed to 146 ccm
front spheres, 450 ccm, 50 -> 170 bar .... to 132 ccm
rear spheres, 400 ccm, 40 -> 170 bar ... to 94 ccm
anti-sink sphere, 400 ccm, 50 -> 170 bar ... to 118 ccm
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
How can removing LHM from the system increase your LHM level?
If all the spheres were changed and completely flat they would would be full of LHM and when removed would remove a total of 400 (fns) + 400 (fos) + 450 (acc) + 400 (ros) + 400 (rns) + 400 (as) = 2450 ccm of LHM. Removing LHM filled spheres from a car removes the LHM that they contain, this would be the minimum LHM lost since some spillage would occur too.
The new spheres would contain 716 ccm of gas when compressed (when the car pressurised its system), so overall the system would lose 2450 - 716 = 1734 ccm of LHM if all the spheres were completely flat and replaced with good new spheres.
Obviously if your LHM level goes up after replacing spheres it means that the old spheres must not have been completely flat, there would be some residual gas in them to force out the LHM, but not enough gas to act as an accumulator / suspension sphere etc.

alexx · Post by **alexx** » 17 Feb 2004, 15:15

You are right. I should say - if spheres were almost flat. Usually, some gas remains inside, so it will extend when you decompress the system and force LHM back to tank. In that case, after replacement, LHM level will rise (almost) for the specified amount.
If spheres were really totally flat, with zero or small quantity of gas, LHM would of course remain inside them.

Gaskin · Post by **Gaskin** » 17 Feb 2004, 19:15

I doubt the spheres were totally flat as the suspension was a bit bouncy but not hard. So I guess as suggested the fluid in the spheres was pushed out when the system was depressurized and the new spheres have not been filled with the same volume. Hence the level increase. Once it stops raining I'll go and suck some LHM out and see if the float drops. Then I might go and see if the ride has improved......
Cheers
Duncan

alexx · Post by **alexx** » 17 Feb 2004, 22:55

Duncan,
some fresh info for you. I didn't check the LHM level since I bought the car 3 months ago, so I did today (well, I knew it was a bit low, because warning light gloved in highest position). I found out the following:
- LHM level is about 4 mm below MIN. At that state, LHM level depth is 138 mm below top of the filler neck. So, at MIN, it would be 134 mm below the neck
- Distance between marks is about 6 mm, so at MAX, level should be 128 mm below the neck
So, you can check this way, to find out is the level float stuck, although not likely. I presume that LHM tank on TD is the same as in 1.8 16v.
And another thing, I measured dimensions of lower part of the tank. It's about 16 x 17.5 cm (hard to measure), so if I didn't overlook something, quantity between MIN and MAX is only around 1.7 dl on Xantia, instead of 4-5 dl on older models (BX, CX...)

Gaskin · Post by **Gaskin** » 18 Feb 2004, 15:13

Alexx,
Thanks for the details, the fact that the fluid level is so far below the top normally suggested that my float was fine and the level was high. Anyway I've removed about 300ml of LHM and the level is back where it should be. From a rough calculation of ~100ml per old sphere extra and 400ml spheres (200ml fluid 200ml gas for a new sphere?) that would imply the old ones were 300ml fluid, 100ml gas ie about half the new pressure.
Driving with the new spheres is like driving a new car. No more pitching and bouncing. I doubt changing the rears will make much improvement, but since it sinks a bit when the engine stops, I guess the antisink is dying so I might as well do the lot.
As ever thanks for all the comments.
Cheers
Duncan

alexx · Post by **alexx** » 18 Feb 2004, 16:22

Ok, Duncan.
About anti-sink, it's normal that the car sinks 1-2 cm before a/s valves close, at least my car ('98) does that (check my explanation a week or two ago). After that, sinking is stopped - well - almost - car sinks with the speed of 1-2 (or maybe 3-4) mm per day.
If this didn't happen before, it's probably due to low pressure in accu sphere, so A/S valves closed earlier.