Xantia strut tops acquired! But mod needed

[aerodynamica]

Hi all, thanks to Mirifioriman I have a replacement pair of Xantia strut tops and gaiters in good condition.

20180707_153744 by Graeme McNulty, on Flickr

I need to convert the new struts with small pipe connections to the larger 10mm pipe fixings for hydractive type.

Here's the hydractive pipe connectors:
20180707_153803 by Graeme McNulty, on Flickr

And the new strut top with small pipes:
20180707_153815 by Graeme McNulty, on Flickr

I've had a look at various old threads on here concerning the difference between the two. Some good info from Chris in Malaga but I'm keen to get an accurate set of info on the dimensions needed for the Hydractive pipe connection. I guess the inner bore is 10mm or a little more and the depth of the union bore can be measured but anyone know the size and thread pitch of the hydractive pipe union nut? It measures at about 15mm but not looked at the thread pitch - looks quite fine.

Any help greatly welcomed!

[white exec]

Hi Graeme,

Just put an XM HA strut top on the bench.
The 10mm HA pipe opening is as follows:

Threaded M16 x 1.5 (I think, but I don't have a tap that big to check), threads go to a depth of 17.5mm from the outside.

Immediately below that is a taper/countersink, which I think is 45deg, but not easy to measure. Check with your own HA pipe end.

From there on, hole continues at 7.5mm diam., to break out on the central drilling.

IIRC, this is a 'compression' joint, seal simply by the outer union on the 10mm pipe belling. No seal.


Caution?
Not sure whether your non-HA tops have the same taper dimensions as HA struts.
You'll remember that John indentified a good many types/combinations of strut and strut-tops across (XM) models.

[aerodynamica]

That's brilliant Chris thanks, just what I needed.

Yes, I'll remove one of the pipes on the car and have a look at the taper.

[aerodynamica]

Caution?
Not sure whether your non-HA tops have the same taper dimensions as HA struts.
You'll remember that John indentified a good many types/combinations of strut and strut-tops across (XM) models.

I just read this again. Do you mean the taper where the top of the strut mates to the strut top to protrude for the nut on top?

I thought the only difference on Xantias was between the V6 and all others?

[white exec]

Just recall that John identified different strut sizes (and designs) across XM range and time - some compatible, some not - and wondered whether this might also apply to Xantia.

[aerodynamica]

Hi Chris, yes I think I remember that - I think it was governed by whether the strut was 22mm or 25mm diameter internal for the XM. IIRC the majority were 22mm but 2.5 litre and V6 were 25mm. I truly hope these items I have are the same as the outgoing pair! otherwise I've just thrown away a wad of cash..

Thanks for the initial thread size dimensions - I can confirm that it is a thread pitch of 1.5 and thanks for the essential inner dimensions especially the depth of the thread. I was wondering about the size of the smaller internal diameter, measured at 7.5 - I was half expecting it to be closer to 10 or more because the pipe is 10mm? (I couldn't really measure this on my car yesterday)

Anyway, thanks again and I'll update on the project

[white exec]

The innermost drilling (at the bottom of the threaded hole, leading into the central strut bore) was 7.5mm - I checked it by inserting a drill bit - and that would be not far off the ID of a 10mm OD pipe.

You might (?) be able to check your strut shaft diameter by measuring the diameter of the strut top hole visible if you remove the top nut. Removing the nut shouldn't allow the shaft to disengage; that will require a hefty hammer blow (use a bit of flattened copper pipe to protect the shaft-end/nut when you eventually hit it!).

Shaft diameter also easily measured by dropping the strut gaiter.

[aerodynamica]

Thanks, my confusion regarding the 7.5 vs. 10 mm bore is that I imagined the 10mm pipe slots into that narrower drilling just in from the olive? Does it in fact merely mate up to it?

[white exec]

The end of the 10mm pipe is forced against the c.45deg taper (countersink) by the threaded insert. It differs from other smaller pipe joints on the car (which have the rubber tubular seal), in that there is no seal - just metal-to-metal contact.

[aerodynamica]

Got you, I suppose the tapered part will have to have a very good finish to seal properly.

[white exec]

Maybe, maybe not. Can't remember the exact shape of the 10mm pipe end now, and its angle, but you'll see it when you undo yours.
Just taken another look at the new strut top here, and the countersink at the bottom of the threaded hole looks to have an angle of 30deg [0deg would be a flat-bottomed hole], which looks to me to be the same as a standard HSS twist drill bit.
The surface of the csk is not dead smooth, but has visible but fine machining lines running round it, which can just about be felt with a scriber point - so it looks as if this surface doesn't have to be perfectly smooth. Clever things, Citroen hydraulic joints, considering the huge pressures they operate at.

[aerodynamica]

Thanks Chris, duly noted

[aerodynamica]

Hello all! It has been many months since I replaced the strut tops with the pair I bought from Dave in Carlisle (mirafioriman) - the pair he had were non hydractive so I set about modifying them to take the hydravtive pipes as per the above chat with Chris. The work was a success after many stages of drilling and tapping the large threads for the hydractive pipe fitting. I had some trouble with the left hand strut pipe because I made a slight mistage with the depth of the drilling but finally worked around it. The question I had about the pipe end sealing on the tapered inner seat turned out to be semi critical in that on the left side I had not given the seat a good finish and it would not seal. I finally improved the surface of it by using a drill with a device to limit its depth and so will 'skim' the surface to improve it. It was never 100% though it did finally seal and I've been running the Xantia since then.
20180901_155342 by Graeme McNulty, on Flickr
20180901_155640 by Graeme McNulty, on Flickr
20180921_165650 by Graeme McNulty, on Flickr
20180921_165724 by Graeme McNulty, on Flickr
20180923_211553 by Graeme McNulty, on Flickr

However, the LH strut pipe has began leaking again and filling up the area behind the strut top with LHM. No amount of tightening of the 17mm pipe nut would fully seal it. And now the 17mm pipe union nut is wrecked from repeated tightening. I finally stopped the leak by adding PTFE tape to the threads and a film of high temp gasket sealant to the pipe end tapered face. It has helt for just over a week.
20190108_185300 by Graeme McNulty, on Flickr
20190110_185401 by Graeme McNulty, on Flickr
20190110_190640 by Graeme McNulty, on Flickr

Unfortunately I now notice that the 17mm union nut has started to crack ridially and now has a crack between every 'flat' on the hex. It's no doubt caused by repeated tightening. I really need to replace the full pipe I think - LH and goes from the strut top down and forward then down vertically at the side of the radiator to meet the Hydractive regulator at the bottom.

Does anyone have one for grabs!!?? I have a horrible notion this is one of those super hard-to-find parts.