10 minute Xantia mod....what a difference!

[isisalar]

Hi guys
Having changed all the spheres which has improved ride considerably on the HDI exclusive, and following a temporary improvement and subsequent deterioration I yesterday discovered that there's still bubbles in the tank.
There are a few suspect spots so the first thing I'd like to do is replace the feed pipe to the pump from the tank. This appears to be a much easier job to do than when I did it on the old 1.9td vsx, the pump being very accessible. Can anyone tell me if this is a straight feed and are the tank and pump spigots the same diameter?
I also have a hacksaw at the ready to do this 10 min mod. Before I start surgery could someone please help with an idiot proof diagram or instructions relating to a hydractive car?
Itching to get it done.
Cheers
Paul

[Mandrake]

The tank to pump pipe comes in a few variations depending on engine Paul, the tank spigot is always 13mm I believe, however the spigot on the pump on most models is about 10 or 11mm, although on the V6 its 13mm.

Some models also use pre-formed bends to route the pipe and are difficult to replace with conventional straight pipe as they can't bend sharply enough, while others have a fairly casual layout for the pipe with gentle curves through plastic guides that can be replaced with conventional hydraulic hose, although even with those ones there is often a single pre-formed right angle bend near the tank that is difficult to route with straight pipe.

I've done the mod on my V6 which is Hydractive and taken plenty of pictures, I would have had a post up by now documenting it but my laptop has died. Writing a long post including several pictures is a bit tedious on an iPad but I'll try to get it done some time in the next few days.

[cc101]

Hi Paul, the pipe diameters are different, if I remember the pump end is smaller than the reservoir end. The mod is the same whether it's a hydractive or not. Remove the filter and pipe head from the reservoir, remove the D shaped filter, remove the two thin plastic return pipes (they just pull out) cut the larger diameter return plastic pipe at an angle to direct fluid towards the side of the D shaped filter. Replace filter and rubber pipes, job done.

Chris.

[Mandrake]

Remove the filter and pipe head from the reservoir, remove the D shaped filter, remove the two thin plastic return pipes (they just pull out)

Those two thin pipes must be specific to the sinkers Chris, my V6 didn't have them (as my pictures will show) and neither did my previous Xantia. Just the one long pipe to be cut!

[cc101]

I stand corrected, ignore the two pipes bit

[Xaccers]

There are a few suspect spots so the first thing I'd like to do is replace the feed pipe to the pump from the tank. This appears to be a much easier job to do than when I did it on the old 1.9td vsx, the pump being very accessible. Can anyone tell me if this is a straight feed and are the tank and pump spigots the same diameter?

Paul,

Get onto Ebay and pick up some silicone pipe used for turbo gauges of suitable length and diameter.
Wrap some duct tape around the ends to protect them and secure with jubilee clips on the duct tape.
I've been using it with Cassy for 3-4 years now.

[cc101]

Another question, is there anywhere on the pump that can draw air in apart from the supply pipe?

[Mandrake]

As promised here is my pictorial dummies guide for Chris's "10 minute Xantia mod", as performed on a 1998 Series 2 V6, although it should be similar if not identical on any other Xantia, the only real difference being the type of pipe that goes from the tank to the hydraulic pump which varies depending on Engine.

Before beginning there is a little bit of preparation needed - most likely your car will still have the original crimp style hose clips like these:



Unless you have the special tool that fits them you're unlikely to be able to reuse them, so you'll need a number of jubilee hose clips of the correct size. The outer diameter of the pipes on mine were:

Pump (front pipe) 19mm, main return hose (2nd from front) 17mm, the three small ones (out of sight below the two push fit pipes) were 13mm.

For the small 13mm ones I found the 12-14mm petrol hose clips from Halfords were a perfect fit:

http://www.halfords.com/webapp/wcs/stor ... yId_255228" onclick="window.open(this.href);return false;

Jubilee style clips in that small a size don't always work so well. For the two larger ones I just used appropriate size jubilee clips that were only just big enough so as not to leave a huge tail.

The second piece of preparation is to be wary of the fact that the rubber on the main two pipes at the front is most likely hard and brittle, and you run the risk of the pipe splitting during disassembly or reassembly, which is exactly what happened to me on the front pipe. So if you don't have a spare car, as I don't, it would be wise to have some hydraulic hose at the ready in case you need to splice and repair the pipe. The inside diameter for the pipe to the pump is 13mm, the return pipe is smaller but I'm not sure exactly what size, probably around 11mm.

Even if the pipe doesn't split it may be difficult to get a good air tight seal when refitted due to the pipe being hard from age and moulding itself to the spigot. It's absolutely crucial that the pipe to the pump is 100% air tight. If its not you'll get air drawn into the pump and the modification will not be successful, in fact you could end up worse off than before! Try to get the pipe and clamp back exactly where they were, or if necessary splice a new piece of pipe in with a metal joiner and a couple of extra hose clips. (On the V6 there is already a 50mm joiner section with two clips, so that 50mm piece can just be replaced, which is what I did)

Before beginning the car needs to be fully de-pressurised, the last thing you want is oil running out of the pipes after the riser is removed... So lower the suspension height lever and let the car idle for at least 3 minutes to de-pressurize the suspension, turn the engine off, then undo the pressure regulator bleed screw half a turn. Do NOT start the engine while the pipes are disconnected or you will have a big mess.

Next step is to disconnect the pipes. I know its possible on some cars to lift the riser out without disconnecting the pipes but I really don't recommend it because (a) it puts a lot of strain on many old very brittle pipes, chances of one breaking is very high, and (b) to cut the plastic tube you really need the riser completely out of the car gripped in a work bench. Here is the retaining clip off, hoses disconnected, and level float removed:



You could actually leave the level float in if you prefer as its protected within a tube, if you want to remove it it turns and unlocks.

You'll now have the tank riser with two filters attached. To release the D shaped filter there is a small wire clip down on the bottom right hand corner of the filter, don't accidentally overlook it as its easy to break the plastic tab:



Once you have the D shaped filter off you'll want to remove the pump filter as well which is a cone shaped filter on the right hand side with 4 plastic lugs, it needs to be rotated to unlock:



You don't actually have to remove this filter to do the mod, however you really should clean both filters thoroughly while you have them out, as they will probably look like this!



Now we're ready to cut the tube. I used a hacksaw, (although you could probably use a hot wire) and I cut it on an angle deliberately as Chris did. I'm not entirely sure whether it needs to be on an angle or which way it should face, the idea is to avoid the flow being directed directly down into the bottom of the tank, also an ellipse shaped cut should lower the velocity of the oil where it exits slightly. I aimed mine towards the side of the filter which is what Chris did. Here is before:



And here is after:



The long side was about 25mm from the rim and the short side about 15mm, but its probably not critical.

Here it is from another angle:



I filed the rough edges off, and made sure to remove all traces of plastic saw dust, as you really don't want that getting into the hydraulic system, even though the filters should catch it.

Here it is with the filters back on for perspective of how the pipe sits within the filter:



Now just re-fit everything. You may run into problems with getting a good seal on the pipe to the pump or it may split so check it carefully to make sure its sealing properly and fix if necessary. On mine the pipe completely split, so I replaced it with a new section:



The pipe arrangement on the V6 is rather peculiar in that they have a 50mm long joiner section from the factory, here's what it looks like under the joiner:



Most other models don't have this arrangement.

Now you need to prime and bleed the pump. Make sure that the pressure regulator bleed screw is still unscrewed half a turn as the pump can't prime under load. If you didn't loose too much oil from the pipe to the pump you should be ok, start the engine and watch in the top of the tank, you'll most likely see froth rapidly form due to the air that got into the pipe while it was disconnected. Let it idle for a couple of minutes to circulate the air out, then close the pressure regulator bleed screw.

Watch the STOP light on the dashboard, it should go out within 10-15 seconds, if it does not go out then the pump is not priming. Stop the engine, open the bleed screw again, disconnect the hose to the pump and pour oil down the hose until its full of oil and repeat the whole process. If you still can't get it to prime you might have a split in the hose like I did, check the hose to the pump really carefully at the tank spigot.

Once its primed and bled you can now lift the suspension and give it at least 3-4 full up down Citrerobics sessions. Job done! Once the system is fully bled you should be able to lower the ride height from maximum to minimum, and not see ANY bubbles in the surface of the tank as the oil rushes back into the tank. (There will be a little bit of froth inside the top of the D shaped filter though, that's ok)

Has this mod worked on my car ? Yes, so far. It's now been 4 days and the ride has been almost crash free even on badly rutted roads, of which there are no shortage in my area. More importantly the ride is a lot more consistent - there is very little if any variation in ride quality from day to day as there previously was.

Don't expect a super floaty magic carpet ride though, as eliminating air bubbles actually improves the damping, the car feels more heavily damped and more stable, so doesn't "float" quite as much, but it doesn't hit potholes harshly any more either. Hard to describe the characteristics exactly but its a very significant change, at least on this car. I'll post an update in a week or two to confirm whether the change has been permanent or not and whether the ride remains consistent.

[isisalar]

Thanks guys that's exactly the information I needed. Just to clarify, the pump feed pipe from the tank is direct, no branches going elswhere?
Off to source some suitable piping elbows and joiners.
Cheers
Paul

[Mandrake]

Yes its just direct.

[Mandrake]

A bit of a follow up on this modification and a tip I've discovered.

For the first two weeks or so after doing the modification the ride was impeccable, almost no crashyness over potholes, smooth ride, well damped at speed.

Unlike before the modification where the ride would get better after Citrerobics and gradually deteriorate over a few days, it stayed exactly the same for the two weeks with no deterioration. I didn't raise or lower the suspension once in those two weeks.

Then about two weeks ago I had the suspension raised to maximum height while I was working on the car and immediately after that the ride was harsh and crashy again.

I tried normal Citrerobics, but it made no real improvement. When I do Citrerobics I normally go from maximum height to normal height as the last step in the process as that's what usually gives the best result, but more on that in a moment.

I left it for a few days and the ride did improve slightly but never fully improved to what it had been after the modification, which left me a bit disappointed.

Then yesterday I decided to fully de-pressurise the suspension and leave it right down over night. Today I then started the car, lifted it to normal ride height and drove off. Eureka! The ride was back to perfectly crash free, very smooth, and very stable and well damped at high speed. In fact slightly better than it was after I first did the modification.

I've done 80 miles along the M77 to Prestwick airport and back today, the ride was absolutely flawless the whole way there and back, at high speed you can really feel an ultra-stable feeling to the handling of the car at speed that's not there when the suspension is in its "crashy" behaviour mood.

When I got home its suddenly clicked in my mind what's going on. The whole problem with the original long pipe that we're cutting short is that it directs the flow of turbulent, aerated oil too far down into the bottom of the tank - close enough that the suction of the pump draws the aerated oil across from the bottom of the return filter area into the bottom of the pump intake filter.

Cutting the pipe short means that the flow of turbulent oil enters near the surface of the oil, keeping the turbulence and air bubbles in the top 2 inches or so of the tank allowing any air to dissipate harmlessly. The oil deeper down in the tank where the intake is situated is thus kept free of air bubbles and turbulence.

However, when the suspension is raised to maximum height the oil level in the tank goes a long way down, its actually fairly near the bottom of the return filter. The end of the pipe is now well above the surface of the oil, so the returning oil lands at the surface of the oil and generates turbulence etc, however because of the low oil level there is no longer enough of a "buffer" region between the surface where the turbulence is occurring and the depth where the intake is.

Thus this modification does not protect against air bubbles recirculating when the suspension is at maximum height and the oil level in the tank is low. I'm not sure that any simple modification would, because there simply isn't enough depth of oil in this condition to provide a buffer that will isolate the turbulent area from the intake area, unless the return and pickup areas were completely redesigned and moved around...

Therefore if you do Citrerobics and the suspension is raised to maximum height and then lowered to normal height as the last step in the process there will be some air bubble entry into the suspension although probably no more than there was prior to the modification...

The solution/workaround is don't do that. To bleed the air out of the system there's no need to lift the suspension right up, simply lower it right down, then return it to normal height. I'm not sure how long it needs to be right down, whether minutes, hours or over night. Over night certainly did the trick but 5 minutes may also work...

If you do need to raise the suspension right up, instead of just going from maximum straight back to normal ride height, go from maximum to minimum, leave it there a few minutes and then back to normal ride height.

So if anyone else who has done this modification noticed a return to harsh ride after raising the suspension right up, simply lower it fully down for a while and then back to normal height, not the other way around...

[cc101]

Good investigation work there Si, another work around could be to lower the car to bottom, brim the reservoir with fluid so when on high the level is not so low, if possible!

Reference to my pump, its ok but it has been changed in the past so wanted to check it's the right one etc.

Spoke to Martin at pleides today, I have a spare set of front hydractive spheres laying about which I'm gonna drill to 1.8mm and chuck em on and see.....

Chris.

[Mandrake]

I wouldn't put any more oil in - mine is at the correct level and when the suspension is fully lowered the oil level in the tank is above the top of the mesh on the filter... you also have to allow for when the car is parked on a slope. If overfilled it will leak out the top of the tank all over the engine bay and ground when the car is tilted on ramps and the suspension is lowered. I know because its happened to me!

Regarding drilling out the holes, I wouldn't drill them to 1.8mm, that will be way too floaty and under damped to the point that it will be a bit unsafe to drive.

The following tables have the damper bypass hole sizes, you might find it useful:

http://homepages.igrin.co.nz/simon/imag ... a_spheres/" onclick="window.open(this.href);return false;

For a standard (not Hydractive) model like yours the fronts are normally 1.5mm and the rears are 1.2mm for a saloon or 1.25mm for an estate.

And yes, the difference between 1.5mm and 1.8mm in terms of damping is huge! It's the cross sectional area that matters not the diameter, so small changes in diameter have a large effect.

[lankytim]

I tried this mod tonight, the ride definitely seems much less crashy and the suspension reacts much more quickly to adjustments on the manual override handle (or whatever it's called), although that may just be because I've cleaned the filters out.

I didn't lower the suspension or de pressurise the system, just removed the pipes, did the work and stuck it back together. I even managed to re-use the the citroen clips by using a weird pair of pincer-pliers.

On start up there was alot of bubbles in the tank but after a few citerobics they all cleared up.

Verdict? So far so good!

[isisalar]

Well done Simon for that. Sounds like there was a reason for Citroens always being sinkers traditionaly then.
Going to try it now.
Cheers
Paul