Citroen XM Forum

The Mk2 struts and strut heads are a little more complex than described above.
The cut over to the thicker strut rods and matching heads was by Mk 2 model starting in 1994 with the 2.5 only.
The model changes to thick rod were progressive and are I believe not correctly documented in the parts records.
That is why the physical check of strut rod thickness/taper size is so important on all Mk 2 models except the 2.5TD.
The later change of strut head at ORGA 7321 was a significant Citroen redesign applied to all strut heads then in production.
It involved a deeper protrusion of the gaiter ring into the wheel arch and a new shorter gaiter to match.
This change increased the structural rubber contact area by around 10% presumably in response to rubber tearing failures.
There was no change in the rods, tapers and oilways so there were no new restrictions on combinations that would fit together.

John

Thanks to you both. I still need to check my 1994 car to see what struts I have there (it's not at home).

If I understand what you are saying, John, the replacement strut top on the drivers side of my 1998 car (from a 2.5L it seems) may still not match the one of the passenger side? The car is still with the garage, so I am unable to check that either.

Can you describe how to determine the differences in taper?

No, What I was trying to say was:-

THICK STRUT ROD/LARGE DIAMETER TAPER
All the thick strut rods have the same taper, same position oilway holes and same thread for the nut at the top.
So they will all fit any design of large hole strut head.

THIN STRUT ROD/SMALL DIAMETER TAPER
All the thin strut rods have the same taper, same thread for the nut at the top.
So any design of small hole strut head will physically fit but oilway holes varied during XM production.
So there are rules and prohibitions about which small hole strut head is permitted with the two types of thin strut rod.

ALL STRUT HEADS have the same chassis fitting so will fit any type of XM.
ALL STRUT CYLINDERS have the same bottom fixing so will fit any XM.
So if a second hand strut and head of the correct hand are recovered as a pair that assembly will fit any other XM.

The easiest way to check the taper is to measure the diameter of the parallel part of the strut rod.
THICK STRUT RODS are 25mm diameter.
THIN STRUT RODS are 23mm diameter.

Strut head TOP HOLE Diameter.
To match THICK ROD taper 20mm dia.
To match Thin ROD taper 18mm dia.

John

With difficulty I got to the Sphere testing work bench.
Found four struts to compare.
3 were XM and one C5 or Xantia.
Only one of the XM ones was thick rod.
Visual examination suggests the XM struts have a symmetrical welded fixing for the drop link.
I decided that two small features determine the handing of the strut cylinder.
The leak off oilway hole is offset to one side of the drop link fixing.
There is a thin vertical welded ridge on the clamp base of the strut cylinder.
This ridge matches small vertical chamfers on the edges of the bottom steering clamp.
Aligning the strut ridge correctly fixes the position of the top of the drop link.
The thick rod recovered one is a passenger side strut probably from a 2.5TD.
(Leak hole to the left Drivers side RHD).
(Leak hole to the right Passengers side RHD).

John

Thanks for all your help - I've printed and am storing that information with the struts.

Lee

xmexclusive wrote: Sun Jul 28, 2019 5:36 pm There is a thin vertical welded ridge on the clamp base of the strut cylinder.
This ridge matches small vertical chamfers on the edges of the bottom steering clamp.
Aligning the strut ridge correctly fixes the position of the top of the drop link.
John

I always thought that ridge was just accumulated dirt and corrosion, not a fabricated location line.
I'll clean one up and have a proper look.
As noted, the leak off port is forward of the ARB link bracket.

All struts have a ridge or locating part at the base of a strut.. Not just citroen but any mcpherson strut car so the strut fits in the hub correctly sided.. And can't be 90deg 100deg or whatever rotationally out of line..