Checking Strut Tops In Situ

[Ciaran]

Afternoon guys, not many people about this afternoon, are you all out doing XM maintenance?

I was looking at my S1 yesterday, when I noticed that the corner of the pipe feeding the passenger side strut top, was polished as if it had been rubbing somewhere.... Alarm bells started to ring... I looked up at the under bonnet lining, and sure enough there was a small area of it worn away.

Strangely though, the worn away but of the under bonnet lining is small and circular, and lines up with the bolt on top of the strut, not the pipe itself... I'm maybe thinking the top was previously wonky, and has been replaced, because aside from the polished pipe, I can see no evidence of problems with the strut top now. Theres absolutely no rust on it anywhere, and it looks and feels solid.
HOWEVER, thats not to say that there's not a problem with the rubber rather than the metal.
So, I was wondering, is there a quick way to check movement with the top in-situ? I'm quite short of time today, and need the car but I would have 5 mins to jack it up and try moving the wheel etc, but I'm just not sure what to look for. I know _some_ movement of the top is normal when steering, I'm just not sure how much is considered normal, or what the signs of failure are, so any pointers would be appreciated. Hopefully I'll get a bit more time tomorrow and can get the tops off the car if necessary, but I wouldn't mind spending 5 mins just checking it today.

Cheers

Ciarán

/EDIT: Doh... just realised this should be in the Hydraulic forum, sorry Noz!

This post has been edited by Ciaran on October 20, 2007 03:45 pm

[Ciaran]

Some pics of it:




The underbonnet lining:



This post has been edited by Ciaran on October 20, 2007 02:59 pm

[colinxm]

Hi Ciarán, just been out doing maintenance on my wifes car - new rear dampers. Anyway, back to your question - jack up the corner you're concerned with, remove the wheel for access and have a look at the underside of the strut top. With the weight of the suspension leg hanging from it you'll easily be able to see if the rubber is becoming detached from the steel.

Hope yours are ok, Colin.

[Andmcit]

I think the shiny pipe isn't unique on just your car - sure I've seen it on many others. The
available room under there isn't very generous to say the least. The visible air gap between the
strut top and the scuttle can be watched, though this may be a little haphazard as the scuttle
can twist if you stare at it hard for too long!!

If you have the car's wheel hanging free with the car safely supported, I'm pretty sure you'll
need to depressurise the system, so it's not all taught and firm under pressure. Get a long lever
such as a trolley jack handle, and lever against the bottom of the wheel and feel and listen to
any movement/deflection on the crown of the strut. It's supposed to rock about when the strut
changes it's geometry when the car steering turns from lock to lock. Bit of a dud design really...

I managed to determine one strut top had a clonk on my 24v V6 using this method and quickly
dispatched it for another that didn't have any movement or noise!!

Andrew

This post has been edited by Andmcit on October 20, 2007 07:10 pm

[xmexclusive]

Hi Ciaran

I agree with Colin, look at the rubber on the underside of the strut head. Your photo are not ideally angled but I cannot see any of the usual rust signs on the top rubber. I think that top rubber rusting and underside rubber tearing are two totally different problems and can happen independantly of each other. In looking at the
underside of the strut head the rubber has a couple of deep (little finger width) grooves cast in the rubber. These will be opposite each other and form roughly two quarters of a circle. It is in the two solid lands that are the other two parts of the circle that you need to look at for cracks in the rubber that look as though they are turning the grooves into a full circle. If there is a full circle crack then it will also be deep and the remaining centre core of rubber is about the same diameter as the central hole in the steel dome the rubber is cast into. In this state it will just be waiting for a big enough vertical force to overcome the friction between the two torn rubber faces. You should be able to see the condition of the underside of the strut head critical circle without needing to disturb the rubber bellows over the strut rod.
I would add that in my experience most XM's have some contact marks on the bonnet insulation when the struts are in good order. You typically only tend to
take real notice of it when you have concerns about the strut heads.

Regards

XMexc

This post has been edited by xmexclusive on October 20, 2007 09:07 pm

[Ciaran]

Evening folks,

Thanks for that, doesn't sound as bad as I thought.

I had the car jacked up at that side earlier (away from home so no axle stands available unfortunately), and with a torch and one of those little dental mirrors, was trying to get a good look at the rubber. From the limited view I got, it 'seems' Ok, but tomorrow I'd like to get it up on stands properly, and will follow the suggestion of getting the wheel off, so I can safely stick my head in there for a proper look.
Out driving earlier I thought I could notice a clonk when steering, but when stopped and listening carefully, it would appear that was the click of the accumulator, which tends to kick in sometimes when the steering is used. I think I'm becoming paranoid and looking for sounds which aren't there TBH

I did attempt to push the wheel up and down and rock it about a bit, but with the car on the jack only, and the fact I have an injured back, the movements I could try were limited really. I'll have to try the jack handle under the wheel tomorrow and push a bit harder to see if it moves, thanks for that one Andrew.

Indeed the strut tops, and indeed the entire car, seems quite corrosion free for it's age. As you mentioned John, there doesn't appear to be any at all above or below the strut top, in fact for a while I was convinced the tops must have been replaced at some point, but I'm not sure. The car has a full Citroen dealer service history from first registration right through to late 2005, but it makes no mention of strut tops in any of it. Then again, they're hardly a service item are they

I'll do some further investigation tomorrow and post the findings (must have a look at the track rod / drop links issue while I'm at it!). Many thanks for the help guys.

Cheers

Ciarán

[Ciaran]

Well, after going ballistic about the S2's back door, I managed to calm down a bit and get a few minutes spare today to check the passenger side strut top.

I jacked it up and removed the wheel as suggested, this enabled me to get in for a good look. Things seem Ok. There's no sign of the 'slots' cracking or spreading into a full circle:
(sorry for the poor focus)


(Believe it or not the rusty looking stuff is actually dusty brown dirt that came out odd on the camera)


One thing I did notice though, is the rubber is aging slightly,and looks a bit dry, with micro cracks in places. Has anyone ever thought about treating the rubber with something? You see those products that can be used for treating dried out door rubbers etc. Obviously there would be concerns about how that kind of thing would react with the metal etc, but it was just a thought.

The other thing I noticed, was the rubber on the base starting to develop a little hairline crack around the circumfrence:



Is that anything to be concerned about?

All in all not as bad as it could have been, though obviously I want to take steps to preserve the tops as long as possible, am still thinking about how to do it though.

Thanks for all the advice

Ciarán

This post has been edited by Ciaran on October 22, 2007 01:01 am

[DerekW]

Hi Ciaran,

The rubber showing the hairline crack is a thin protective film that covers the metal of the strut top to prevent corrosion. Problem is that when this film cracks it allows damp, road salt and all the other nasties to get to the steel and that's how strut top corrosion starts. I think XMexclusive is one of the experts on this subject and he may disagree with me, but perhaps you should check for rusting under this crack and then reseal it, maybe with something like polyester resin.

Is silicone spray compatible with rubber?

Derek

[Ciaran]

Excellent idea Derek, would be interesting to see if it were possible to reseal or recondition the rubber, though obviously you'd have to be very wary about trapping any moisture in there when sealing it up. British Leyland bodywork, anyone?

Speaking of the rubber, I've often seen these products you can use on the likes of door and sunroof seals, which is supposed to rejuvenate the rubber and prevent cracks etc. Has anyone ever thought of using this kind of thing on strut tops, or would that be a bad idea?

Theres a rubber specialist place a few units down from a company where I often stop off to do jobs. Next time I'm down there, I might take in a spare strut top and enquire to see if they could make up some kind of replacement coating if the OEM rubber were to be taken away or whatever.

Ciarán

[wirdy]

Choose a nice dry day and pull off all the loose rubber (it's now a haven for trapped moisture to do its worst).
Then reseal the whole lot with a air curing RTV sealant. This has worked fine for my Xantiae and XM's.

The grey RTV is generally cheaper than the black stuff and soon gets covered in road grime anyway.

The MOT man noticed it freshly-applied on the xantia and it drew the comment that preventiion is better than cure

Quite economical as you can also use the same stuff on any loose rubber on the tops in the engine bay.

[Ciaran]

Nice dry day eh... not many of those around here, but will have to look for one!

When you say RTV sealent, is that just the standard silicone 'bathroom sealent' type stuff in a gun, or is it more specific?

Did you remove your tops to do them?

Cheers

Ciarán

[wirdy]

Ciaran - PM me your address, I have a tube here that will do both your struts.

It's Mil-spec silicone sealant, probably not dissimilar to domestic sealant but this stuff adheres much better.

Didn't have any black left in our stores so this is the white stuff if you're not worried about aestetics.

This post has been edited by wirdy on November 06, 2007 01:00 pm