Gas strut failure?

Hi all,
I gave the Meriva it's annual pre MOT wipe over the other day and when
I opened the tailgate the next day it was heavy / didn't stay? ;-(
Now I remember seeing some sticky gunge at the end/s of both struts so
I'm guessing they can leak and why they lose their 'ooompf'.
So could it be because it's cold they have lost power or just
coincidence? I ask because I think it's happened before and then must
have cured itself?
I think they are only a tenner a pair so not a biggie but I was more
interested in their failure mode?
Cheers, T i m
Reply to
T i m
Temperature reduces the gas pressure, which will slowly deteriorate with age and leakage anyway, so you usually notice when it is cold, just as batteries show their weakness when it gets cold.
Reply to
MrCheerful
Yeahbut, would you predict them behaving like a 'summer battery' and to start working again as soon as it warms up?
It wasn't particularly warm when we cleaned the inside of the car (the outside was done by the car-wash) and the tailgate was up and down a few times during that period with no issue with no issue. The next day, the strut(s) won't support the tailgate?
I did wipe the struts down with my damp cloth but being they were sealed I couldn't see how that could impact them negatively?
Could any residual damp on the shaft have frozen and the resultant ice damaged the strut seals?
Cheers, T i m
Reply to
T i m
If the leak is due to contraction of metals, seals going stiff etc, once the gas escapes it is gone. When the strut warms up it doesn?t come back.
A ?weak? battery is different, the reaction does recover a bit in warm conditions, the engine oil isn?t so viscous etc.
Equally, struts do fail. Maybe it was just the time this one felt it had had enough ;-)
Reply to
Brian Reay
The OP could just carry a pair of mole grips on board, they keep the tailgate open even on a windy day.
Reply to
MrCheerful
On Thu, 31 Oct 2019 11:17:02 +0000 (UTC), Brian Reay wrote:

Sure.
Quite, but the gas could have lost some of it's pressure because of the cold and may return when warm?
Accepted.
Of course, however, this tailgate has two struts so the question is, can one still hold it up? If no, then both have failed at the same time? Coincidence ... or some (fatal, atm) external event that have impacted them both simultaneously over the same night?
When I'm not doing loads of other things, I'll take each off in turn and see what's what (probably as I replace them both). ;-)
Cheers, T i m
Reply to
T i m
I was thinking of some suitable diameter plastic tubing, just under the same length as the open strut piston shaft and split down it's length ... to pop over the strut shaft when fully open?
New struts should be here next week. ;-)
Cheers, T i m
Reply to
T i m
Not if it has leaked out, at least if too much has leaked out.
I think the relevant Law of Physics is Gay Lussac?s Law but I could be mistaken, it is a long time since I studied such things. As I recall, it is a linear rule, if the volume is constant so perhaps one of the other Laws features as well until the strut comes to rest. Either way, if the gas has leaked out, there won?t be enough to exert the required pressure, especially if the temperature is also reduced.
Reply to
Brian Reay
I tried the split plastic tube and the tailgate weight just opens up the tube and down comes the tailgate, while mole grips work well :)
Reply to
MrCheerful
Quite possibly only one has lost its oomph, but one, even a new one, will not hold up a tailgate. It is really hard to judge knackered struts off the car, unless there is absolutely nothing left of the gas pressure.
Reply to
MrCheerful
I did wonder about that.
Or just hold it up while 'she' gets things in or out. ;-)
Cheers, T i m
Reply to
T i m
On Thu, 31 Oct 2019 22:05:41 +0000 (UTC), Brian Reay wrote:
No, not that ...
Yes, that one. ;-)
Understood.
Ah, now there's a thing ... ;-)
Cheers, T i m
Reply to
T i m
Ok.
Interesting, thanks.
TBH, I can't remember if it felt that the struts had lost their 'oomph' over the time I've had the car but it's possible they / one has.
I'd say the tailgate has been pretty predictable, up to the time when it just didn't stay up and felt like it would take you head off if you let it go. However, it's possible that it lost some of it's lifting ability a while back (and I've since forgotten).
Like, it's possible that it used to actually lift the tailgate open itself from say the 1/4 open position, but as far as I can remember I've had to pretty well open it most / all the way and the struts would then hold it there?
This is one of those things that if it first happens when you are busy doing something ... but you can actually carry on, mostly unhindered ... you get used to it?
It's like the aux belt /
water pump / alternator that screeches for the first 10 seconds that you leave (till it fails completely) or the noise that goes away (like the alternator overrun clutch on daughters Transit Connect). ;-)
Cheers, T i m
Reply to
T i m

I think that's sage advice in many circumstances. where you know the worst-case consequences (assuming you don't know exactly what the problem is and / or can't fix it cheaply or easily).
Like daughters (now) 200,000+ mile, 1.2, 01 Corsa.
We were loosing water from the head gasket so applied some water seal gloop and it's lasted another good few thousand miles so far. Little to lose etc.
It failed the MOT with an 'excessive oil leak (more than a 50mm diameter puddle over 5 mins or some such?) from the engine (rear crank seal most likely) so we applied some oil leak stop gloop and so far, so good.
So, in those cases it was the outcome of the treatment we were interested to see how they developed. ;-)
Cheers, T i m
Reply to
T i m
Surely almost all oil leaks are just active corrosion protection
I seem to recall some production vehicle venting the crankcase into the chassis rails although this might have been nothing more than something discussed in the pub.
Reply to
The Other Mike
In article ,
Certainly the case on my SD1, which has a very heavy tailgate and bonnet.
On a hot day, you have to take a bit of care opening the tailgate to avoid it bashing you on the nose. ;-) But they are just about adequate on the coldest day.
The front hinged bonnet uses a special type, which appear to 'lock' in the open position. Standard ones let it blow closed in the wind all too easily.
Reply to
Dave Plowman (News)
Indeed. But best way to test a pair is to remove one and then use the tailgate to test the other, as it will still hold up a good proportion of the weight if it is any good. By swapping you can usually spot if one is significantly worse.
I've always thought it is a pity that there isn't an obvious code for marking them up. I suspect that they usually contain the same pressure, and most care ones are the same OD (and therefore presumably ID), in which case they only have two parameters, free length and compressed length. (I have some on a horsebox conversion and I suspect the builder just welded brackets to fit what he had to hand).
Reply to
newshound
Doesn't the SD1 bonnet have a sort of four bar linkage rather than a single pivot "hinge"? That goes into a sort of over-centre toggle to help it hold.
Reply to
newshound
In article ,
No - just single pivot hinges. Some models have a rod system to latch the bonnet open, though. Could be the AC compressor goes where it is, hence the special struts.
Reply to
Dave Plowman (News)

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