strut mounting, strut monting

[White Exec]

Hi John,

First, real thanks for your detailed reply, especially at the hour you sent it. It answers lots of questions, and I'm only just realizing, from Noz and others, just how much work you've put into this essential item. I've spent a good many hours working through the design and loading of the existing arrangement, and have come to exactly the same conclusions that you have. I've also looked at some more elegant possibilities for add-ons to prevent serious damage in the case of burst-through by an existing unit.

Last night, though, I trawled through the appalling chronicle of woe on the frenchcarforum.co.uk site, which details the collapse of the Xantia. It makes for ghastly reading.

I have to say this: Citroen should be ashamed of themselves, to have designed a critical component, bearing the full weight of their prestige car's driving and driving/braking stresses, which incorporates rust-prone steel, encased in a flimsy 'rubber' rust-trap. You might as well wrap your cherished steel in a condom, and leave it on Brighton beach! (Please don't expand on this, anyone...)

As several folk have already commented, the design is further seriously flawed by placing the 'rubber' under tension and stretch (in rebound), and also loading it axial-vertical in what amounts to an invitation to shear. Everyone working with 'rubber' suspension and bushing knows that rubber has its maximum life and durability in compression, and the Citroen component just does not obey this rule.

So, totally agree that (a) secondhand units are questionable, and will exhaust, and (b) new units (expensive) will also disappear. There are also risks around "rebuilds", e.g. weak spots alongside repair and other new welds. So it's remanufacture, then.

The proposal for the Latvian rebuild being around a new steel baseplate is a really good move. Decent steel, revised profile, and anti-burst-through all need to be incorporated. Low price means quantities. Put me down for one pair, please, which I will put on the shelf, and might well install as a preventative step. At the right price, we can shift hundreds of units, perhaps more.

There's a good track record for aftermarket polyurethane bushing components, from many manufacturers, so let's hope Latvia can match this. (If they cannot, others will, so let's retain control of this.)

I would like to look at a cross-sectional drawing for the Latvian rebuild, showing all the modifications (new profiles, rings...). Can you point me in the right direction, or post this?

Again, real thanks for all this, John.

Chris

[xmexclusive]

Hi Chris

Have a look on the other XM site "Citroen XM strut mount refurbishment" under general technical. I have spread my posings on this subject between the two sites. Much of the replies made to me by KingAS the designer and refurbisher have been published on the sites including photos and cross-sections. I found the responses quick, positive, technically competent and most important willing to make changes to meet a specific customers requirements. Anything extra you need to know ask direct.

Regards

John

[xmexclusive]

Hi Chris

You asked about supply of refurbished strut heads.
I personally have got a small batch refurbished so that I could assess actual examples and some of the various options available. Hand change, metal repair work, elastomer finish and quality etc. My aims now are to obtain sufficient refurbished heads for my needs and if possible also collect and supply KingAS with a reasonable stock of various types of head ready for refurbishment. I do not wish to supply and sell on repaired heads but do have a friend in the Citroen owning community who is considering taking this on.
It did at least start the ball rolling with the refurbishment.
I seriously doubt that we will ever justify a production run of new baseplates nor will the Xantia lovers despite their greater need. My reasons are inability of sufficient XM owners to group refurbishment purchases and with Xantias low Citroen prices coupled with high volume of purchase will keep Citroen production going. If the two types of baseplate were the same it might be a different matter.

John

This post has been edited by xmexclusive on March 11, 2011 05:43 pm

[xmexclusive]

Hi All

Just a copy of an update I have just made on the other Forum.

From reports I have had a rumor seems to have got spread at the Weatherby Rally that there is now a sole agency UK supplier for the Latvian refurbished strut heads.
I checked this with KINGas this morning.
He replied that a request for sole agency was made recently but was refused as it is not their company policy to grant such agreements.

John

PS

On thinking a bit more about this the only source of information that I am aware of is the postings on these XM sites.
Much technical work and analysis has gone on here to work up a viable option for strut heads. I would be very upset to think one of our readers has decided to use that information to try to corner the market rather that contribute with us all to the technical development of a strut head solution.

In the next few weeks I was hoping to read and publish the various XM 2.5 ECU EPROM contents. I will still read them but will now only summarise my findings.
It seems that you can be too free with information.

This post has been edited by xmexclusive on May 23, 2011 01:34 pm

[citroenxm]

QUOTE (xmexclusive @ May 23, 2011 01:22 pm) 

It seems that you can be too free with information.

Ive had these feelings for years, and I find it extrodanry in a community were we all are a Fan of the same Marque that people in the same community WANT to be greedy and monopolise an opportunity when it arises..

Paul

[steelcityuk]

Would KINGas not tell who tried for the sole agency? My feelings are if they are found they should be banned from all the Citroen forums.

Sounds very much like what happened to the disc that Noz put together.

Steve.

[xmexclusive]

Hi Steve

The question did not need to be asked of KINGas.
I do not think banning is justified either.
Just as well because I could actually have done that on the XM forums.
There are quite considerable costs and logistics in setting up this end of a refurbishment chain. I can understand a need for some to protect any investment they make by exclusivity. It is the lack of announcement of intent to us that I choke on.
I still think that this is minor compared to the blatant ripping off of Noz's hard produced disc.

John

[Jan-hendrik]

[QUOTE name='minijet' timestamp='1284328658' post='38836'].
This mess was the result of strut rubber fatigue......



It's my second strut top failure.
First one was due to rust.

I could never understand how strut tops were put together, but this latest failure has given me the opportunity to have a better look at strut top construction.......




I've now come to the conclusion that a strut top is made up of five main components..........



1. The inner steel cylinder which sits on the strut.
2. The main clamping plate - the part which normally rusts and fails.
3. The solid rubber block that connects parts 1 and 2 together and will eventually/inevitably fail.
4. The steel dish.......I don't know the purpose of this part.
5. The top section which houses the hydraulic connections.

I don't see the inner steel cylinder (#1) in the part list illustrations for series 1 nor 2. Is this a very early version before ORGA 4557?

This post has been edited by Jan-hendrik on July 16, 2012 03:51 am

[xmexclusive]

Hi Jan

The inner steel centre (part 1) and the top section (part 5) are factory assembled as one component.
The cast metal top section contains an internal circular groove.
The pressed metal centre cylinder is a tight fit inside the top section.
In the factory they press a ring of dimples so that the cylinder is locked in the groove.
Pre 4557 they only used 4 dimples then changed to 10 dimples.
The change was because the early 4 dimple ones were prone to failure.
I think Noz put up a posting about this feature of strut head design.

John

[Jan-hendrik]

Thank you for that reply, John.

BTW, my dealer here informed me today the strut tops are still available from Citroen. Priced at 63,000 and 75,000 yen for left and right respectively! These are for my Series 2.

[xmexclusive]

Hi Jan

Odd to have such a price differential for mirror image products.
Guess that one is on stock in Japan and the other has to come from France.

John

[Jan-hendrik]

Odd indeed, John. The dealer was puzzled too. The way I understood it, both parts are on BO. Perhaps they come from different suppliers in France. This could also indicate they are now in very short supply, or is it they simply come from different batches? Anyway, those anxious about replacing the tops should hurry, if they value keeping their XM long enough to justify the expense

The rebound stop and bump spacer I mentioned here: http://www.club-xm.co.uk/forum/viewtopic.php?f=7&t=3812 are also still available, but on BO.

[Jan-hendrik]

I took off the LH strut top and compared it to the spare from the '98 XM. They looked exactly the same. Excellent condition, no tears in the rubber. Not a spot of rust.
I am still confused however about the parts rebound stop and bump spacer. Did not find these as listed in the part cataloque. Instead there was an orange colour rubber sleeve:



(photo taken from Dutch forum)

Can anyone explain?

Oh, and I still haven't found the origin of the noise.

This post has been edited by Jan-hendrik on July 18, 2012 07:05 am

[xmexclusive]

Hi Jan

I have only ever found that orange "bump stop" between cylinder and head.

The "rebound stop" is an integral part of the cylinder.
It is a spring that operates between the top and bottom bearings of the cylinder as the strut becomes fully extended.
The top bearing is fixed to the top of the cylinder and has a central hole for the strut rod.
The bottom bearing is fixed to the bottom of the strut rod.

As well as the orange bump stop the cylinder has a spring and hydraulic stop in the bottom.
These components come into operation as the strut fully closes.

This information comes from the original XM technical bulletin.

John

This post has been edited by xmexclusive on July 18, 2012 10:53 am

[Jan-hendrik]

Hi John,

Yes, I get it now! Thank you.
Something has been written on the other forum as well