Air bubbles in the LHM gives harsh ride?

Mandrake · Post by **Mandrake** » 07 Jul 2007, 22:13

What kind of tape did you use ?

I can't think of many kinds of tape that will remain stuck while submerged below mineral oil... in fact I'm sure some kinds would disolve in the oil!

Or is this just a temporary test ?

Regards,
Simon

bernie · Post by **bernie** » 08 Jul 2007, 16:05

Mandrake wrote:What kind of tape did you use ?

I can't think of many kinds of tape that will remain stuck while submerged below mineral oil... in fact I'm sure some kinds would disolve in the oil!

Or is this just a temporary test ?

Regards,
Simon

Thanks for pointing that out Simon but it will be temporary

bernie · Post by **bernie** » 10 Jul 2007, 17:02

V2

mpr1956 · Post by **mpr1956** » 10 Jul 2007, 21:03

Well Bernie.. I await your results with interest... if you can replicate PPrado's results, then I for one will be quite excited, as I have varying ride quality from day to day.. -I never thought it could be caused by my "frothy" LHM return !! (93tdsx with FDV) Regards, Martin

Mandrake · Post by **Mandrake** » 10 Jul 2007, 23:11

bernie wrote:V2

Looks great

If only I had a spare tank to experiment with. I don't suppose you have the diameter and length of the black pipe that you've clamped your hose onto ? If I knew those figures I could go and buy some suitable pipe without first having to take everything apart to measure it. (On my tank the middle can't be lifted out without disconnecting all of the hoses

)

I was thinking too that having a reasonably large diameter is good, as it reduces the velocity of the oil where it comes out so it wont splash/froth unnecessarily on the surface.

Was I right when I heard that there was a split on that black pipe ? Does it also have a full size hole at the bottom ?

As far as my simple "pipe through the top" makeshift arrangement is going - its been a week now and the stop light is still going off after about 3 seconds from 8 hours standing and 6 seconds after overnight standing, and lifting is still a lot quicker than it used to be. So that much seems certain.

As for the ride - I wouldn't say its perfect, but it is pretty good, and pretty consistent too, so far, given how makeshift my arrangement is.

I still have the issue of the front hydractive pipes to sort out - the steel part below the joint that clamps onto the wing I just noticed is actually pressed up against a bracket on the body metal to metal, and free to move around.

I'm sure that this will be causing a nasty noise when hitting manholes on that side, and every time you turn the steering and the strut leans forwards or back that pipe will be grinding its way along the bracket as it isn't secured..

I still can't work out what kind of fittings I'm going to get to secure the clamp though ? The panel has a small square hole of about 10mm, but both sides on mine were only secured by a medium size self tapper screw into the panel when I got the car - clearly insufficient, and some kind of bodge. Perhaps some kind of self expanding captive nut would do the trick?

Does anyone have a picture of what the original attachment looks like ?

Regards,
Simon

bernie · Post by **bernie** » 11 Jul 2007, 11:54

Mandrake wrote:
bernie wrote:V2

Looks great

If only I had a spare tank to experiment with. I don't suppose you have the diameter and length of the black pipe that you've clamped your hose onto ? If I knew those figures I could go and buy some suitable pipe without first having to take everything apart to measure it. (On my tank the middle can't be lifted out without disconnecting all of the hoses )

Same with mine Simon, I have to disconnect all the pipes Sorry I did not measure them. I could send you a length of my pipe as I have spare

I was thinking too that having a reasonably large diameter is good, as it reduces the velocity of the oil where it comes out so it wont splash/froth unnecessarily on the surface.

Was I right when I heard that there was a split on that black pipe ? Does it also have a full size hole at the bottom ?

Yes the split is around 75% of the height on the opposite side to my white pipe split.

As far as my simple "pipe through the top" makeshift arrangement is going - its been a week now and the stop light is still going off after about 3 seconds from 8 hours standing and 6 seconds after overnight standing, and lifting is still a lot quicker than it used to be. So that much seems certain.

As for the ride - I wouldn't say its perfect, but it is pretty good, and pretty consistent too, so far, given how makeshift my arrangement is.

I still have the issue of the front hydractive pipes to sort out - the steel part below the joint that clamps onto the wing I just noticed is actually pressed up against a bracket on the body metal to metal, and free to move around.

I'm sure that this will be causing a nasty noise when hitting manholes on that side, and every time you turn the steering and the strut leans forwards or back that pipe will be grinding its way along the bracket as it isn't secured..

I still can't work out what kind of fittings I'm going to get to secure the clamp though ? The panel has a small square hole of about 10mm, but both sides on mine were only secured by a medium size self tapper screw into the panel when I got the car - clearly insufficient, and some kind of bodge. Perhaps some kind of self expanding captive nut would do the trick?

Does anyone have a picture of what the original attachment looks like ?

I'll try to get a picture

Regards,
Simon

Post by **CitroJim** » 11 Jul 2007, 16:52

Excellent work Bernie

I've been following this thread with great interest and recently I've noticed my ride changing day-by-day and even sometime during the day. This morning on the way to work the ride was nothing special but this evening on the way home it was like riding on oiled silk

This is whilst running on Hydraflush so it'll be intersting to see how it goes with new LHM in it. I've still got 600 miles to go before then

pprado · Post by **pprado** » 11 Jul 2007, 23:52

How about everyone that tried it out reporting their experiences?

For me:

Stop light going after 2 to 3 seconds, height changes respond quickly, the ride is very consistent - not good yet but I still need to do some things, among them one I would love is hydraflushing the system but unfortunately TOTAL Brazil does not even know what is this.

I have a strange side effect where the steering wheel becomes somewhat stiff at the ends sometimes... I think I have a leaky piston :-/

Hey Simon, I dunno if you closed the LHM tank around the pipe - if you did that, this may cause backwards pressure on the return lines. Better to get some LHM cap, cut 2 holes on it, and pass the clear pipe on one and the tiny overload tube on the other.

pprado · Post by **pprado** » 12 Jul 2007, 00:50

To help: i could fit a 1/2 pol. L-junction to the end of the pipe after joining the slit on the end - so the downpipe is slightly larger than 1/2 pol.

I think that that kind of tube that is used to hold wires on construction ("conduite" here) may be adequate for this job but they are not made to be sealed.
However I am starting to think in heating a plastic tube and molding it in U...

steelcityuk · Post by **steelcityuk** » 13 Jul 2007, 10:05

I'm still watching this thread even though the Xantia's gone now. Neither of my XMs suffer from this problem of intermittant hard ride. The only difference I can see is the shape of the LHM tank, could this tie in with the latest findings?

Just to add more info the Xantia had been serviced much better than either of the XMs.

I can only describe the ride in the XM hatch as sublime, the estate isn't as good but this could be because of the sphere specs or is it because it has 205 tyres same as the Xantia did whereas the hatch has 195s?

Steve.

Mandrake · Post by **Mandrake** » 13 Jul 2007, 11:31

pprado wrote:To help: i could fit a 1/2 pol. L-junction to the end of the pipe after joining the slit on the end - so the downpipe is slightly larger than 1/2 pol.

What on earth is a 1/2 pol ?

Don't you have millimetres or inches over there ?

Regards,
Simon

pprado · Post by **pprado** » 13 Jul 2007, 12:36

Mandrake wrote:
pprado wrote:To help: i could fit a 1/2 pol. L-junction to the end of the pipe after joining the slit on the end - so the downpipe is slightly larger than 1/2 pol.
What on earth is a 1/2 pol ?

Don't you have millimetres or inches over there ?

Regards,
Simon

My bad! inches are "polegadas" here hehehehehe

pprado · Post by **pprado** » 14 Jul 2007, 03:09

steelcityuk wrote:I'm still watching this thread even though the Xantia's gone now. Neither of my XMs suffer from this problem of intermittant hard ride. The only difference I can see is the shape of the LHM tank, could this tie in with the latest findings?

Hey SteelCityUk, I owe you my idea - I had it by looking at your pictures with bubbles =)

Could you tell if the XM reservoir has the return flow output very near from the pump input? That is the main thing being avoided.

Just to add more info the Xantia had been serviced much better than either of the XMs.

I can only describe the ride in the XM hatch as sublime, the estate isn't as good but this could be because of the sphere specs or is it because it has 205 tyres same as the Xantia did whereas the hatch has 195s?

Steve.

Although the tires always do difference, I believe they would not make so much difference on an hydraulic car... might be wrong, though

jorgy · Post by **jorgy** » 14 Jul 2007, 04:15

Hi all

quick intro, I'm fighting the same problem 2 years now.

Hi Steeve, as u know I drive an XM Hydra II an it has the problem. Agree with Prado that tyres are not the problem. My XMs behavior is volatile -as described by others-. I've had it working perfectly (as it should) for a day and was on same tyres.

Now I've eliminated all electronic/electirc possibilites, and tuned pressure regulator to correct pressure range 145-170 bar (with gauge), and even fitted a one-way valve to feed the front e-valve to make sure it doesn't suffer from pressure loss from elsewhere in the system. All spheres equally measured + they r the correct ones. Height also checked and adjusted, also changed bronze bit on linkage that gets sticky on XMs-.

My thoughts curently are: major probability, this problem is related to an abnormal loss of pressure somewhere (which possibly creates the bublles in LHM and also quickly destroys its mechanical qualities as oil overheats at the point of leakage). My reg. clicks every 13secs so I have a loss somewhere -I'll check returns and find out soon, and replace relevant component-. Question: are all sufferers' cars happening to suffer from low cycling time?

If not *indirectly* LHM-related as above, my other bet is on sticky struts -yet undocumented on XMs-, but bit unlikely as I had my car being a magic carpet for 2-3 days over last 2 years with those same struts.

FIY I found out that best practice in hydraulic systems is oil return being under oil, not above it -any spilalge creats foaming-. I append the links.

http://www.mcnallyinstitute.com/10-html/10-10.html

http://www.lube-tips.com/challenge/2003-01-22.asp

XM tank looks well designed according to above references, important point seems easy LHM sunction from pump ie: clean and good tank filters, airproof LHM sunction pipe, tank breather (filler) cap not stuck (subpressure will be created and pump may tend to suck from other points except of LHM tank).

Relevant cases I found all over the English and French net: a CX where a guy had similar (?) problem and he opened up struts to find a "syrup" substance which he cleaned and car became soft as it should; also a BX guy found an LHM filter had a whole and putting new filter sorted him out.

That's all very quickly, I'll keep you posted as I intend to fix components that need fixing on mine (prob new brake valve) and buy new tank filters and put LHM (I m on hydraflush now). Will even remove and clean hydractive blocks if I get no result -suspect the valves+ball in there might be sticky as CX case above, but difficult for hydraflush to clean this-.

regards

George

ps. Bernie your tube's "nerves" instinctively don't look best for flow?

pprado · Post by **pprado** » 14 Jul 2007, 04:43

jorgy wrote:
My thoughts curently are: major probability, this problem is related to an abnormal loss of pressure somewhere (which possibly creates the bublles in LHM and also quickly destroys its mechanical qualities as oil overheats at the point of leakage). My reg. clicks every 13secs so I have a loss somewhere -I'll check returns and find out soon, and replace relevant component-. Question: are all sufferers' cars happening to suffer from low cycling time?

Mine at least is, and changed dramatically when I put the bubbles far away from the suction pump... But it appears that I have another leaky point.

FIY I found out that best practice in hydraulic systems is oil return being under oil, not above it -any spilalge creats foaming-. I append the links.

http://www.mcnallyinstitute.com/10-html/10-10.html

http://www.lube-tips.com/challenge/2003-01-22.asp

XM tank looks well designed according to above references, important point seems easy LHM sunction from pump ie: clean and good tank filters, airproof LHM sunction pipe, tank breather (filler) cap not stuck (subpressure will be created and pump may tend to suck from other points except of LHM tank).

Very interesting points... I certainly agree that the return will make less bubbles by impact with the reservoir oil by having the return submerged, rather than on the air. However, the bubbles are being generated before arriving on the tank and because they arrive too near to the suction point, they get back on the system again - the cycle amplifies them - lots of air on all systems.

Relevant cases I found all over the English and French net: a CX where a guy had similar (?) problem and he opened up struts to find a "syrup" substance which he cleaned and car became soft as it should; also a BX guy found an LHM filter had a whole and putting new filter sorted him out.

That's all very quickly, I'll keep you posted as I intend to fix components that need fixing on mine (prob new brake valve) and buy new tank filters and put LHM (I m on hydraflush now). Will even remove and clean hydractive blocks if I get no result -suspect the valves+ball in there might be sticky as CX case above, but difficult for hydraflush to clean this-.

Simon's suggestion to check HA valve return might help also...

Good luck!