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Regassed AFT Struts
Posted: Sun Feb 07, 2010 10:22 pm
by Rhod
Caution - a tale of woe follows
Like many others, my AFT often needs a helping hand to get it up the last couple of inches, something that I decided was in part due to the extra 10-15kg of roof-rack up there.
So, following a discussion on the forum a few months back, I decided to fit a set of uprated struts from SGS, which had been gassed to approximately compensate for an extra 15kg.
I finally got around to fitting them today.
The first thing that I found was that, to remove the old strut, the roof has to be pushed up slightly further than it's normal position since the strut is still trying to extend (unless you can figure out a way to compress the strut - I couldn't.) I did this by pushing the roof slightly with my back while using both hands to remove the strut - working from inside the roof space. What I didn't realise was that I should have released the roof tent from the top of the AFT first. Consequence - a nasty ripping noise as the tent ripped just below the webbing attachment point at the front (just below the middle zip

Not being able to do anything about that, I carried on & replaced both struts. When nipping off to get something with one new & one old strut fitted I did notice that the roof was distinctly higher on the new side.
Both new struts fitted & time to check that the roof lowered. It didn't

The motors worked briefly, but no movement. Oh dear, how unfortunate, I muttered to myself & set about swapping back to the original struts. Operation completed & the roof descends & ascends as required.
So unless you have a really heavy rack/box uprated struts are not the answer. If you DO have a heavy roofbox & want to try uprated struts then I have a pair going very cheap

Re: Regassed AFT Struts
Posted: Sun Feb 07, 2010 11:18 pm
by mikeonb4c
Re: Regassed AFT Struts
Posted: Mon Feb 08, 2010 12:45 am
by dandywarhol
Ouch!
Re: Regassed AFT Struts
Posted: Mon Feb 08, 2010 1:33 pm
by missfixit70
That's a double blow

, I'm sure this was discussed as a possibility when this has been discussed in the past, that the motors may struggle to pull it down again, what a bu66er.
Re: Regassed AFT Struts
Posted: Mon Feb 08, 2010 3:09 pm
by mikeonb4c
You would think that provided the correct load was estbalished, and same load was on the roof when it was both raised and lowered, then the motors might still work fine. This would mean either:
*Ensuring the roofbox contents were in the roofbox during opening and closing
* Having some kind of spring/bungee that would simulate the load when raising or lowering
* Having some kind of weight that would simulate the load etc.
An interesting challenge

Re: Regassed AFT Struts
Posted: Mon Feb 08, 2010 5:23 pm
by bongoing-mad-simon
Rhod you have a pm
Re: Regassed AFT Struts
Posted: Mon Feb 08, 2010 10:53 pm
by Rhod
missfixit70 wrote:That's a double blow

, I'm sure this was discussed as a possibility when this has been discussed in the past, that the motors may struggle to pull it down again, what a bu66er.
Yes - and I disputed that theory
Still, someone has to test these things out I suppose.....
I think that the problem is that it's difficult to estimate just how much gas the struts need in relation to the extra weight - I obviously over-estimated a bit. SGS do an "adjustable" strut which has a valve through which you can vent off gas until the pressure is correct for your needs. These might work, but I'd be wary of managing to get the same pressure in each strut - having seen how different struts on each side can distort the roof.
The roof canvas is probably repairable, but since it's at a stress point and may be difficult to get watertight, I've opted for a replacement one which Bellhill happened to be selling. I figured that by the time I got the damaged one to a tent/sail repair company who could do a decent quality repair, it probably wasn't going to be much cheaper. Plus I'd probably be lying awake worrying every time the wind got above force 2 with the roof up

Re: Regassed AFT Struts
Posted: Mon Feb 08, 2010 11:01 pm
by bigdaddycain
Rhod wrote: The motors worked briefly, but no movement. Oh dear, how unfortunate, I muttered to myself & set about swapping back to the original struts.
I'll bet you said a little bit more than that Rhod!
I wouldn't have imagined that could have happenmed until you kindly pointed it out... But when you think about it, yes, with the power of hindsight, if the struts have been uprated, then they would also need added downward force (via roofload) to assist the motors on the way down... Can you imagine trying this in the summer when the gas had expanded (therefore even more effort required)

Re: Regassed AFT Struts
Posted: Mon Feb 08, 2010 11:06 pm
by bigdaddycain
Rhod wrote:missfixit70 wrote:That's a double blow

, I'm sure this was discussed as a possibility when this has been discussed in the past, that the motors may struggle to pull it down again, what a bu66er.
Yes - and I disputed that theory
Still, someone has to test these things out I suppose.....
I think that the problem is that it's difficult to estimate just how much gas the struts need in relation to the extra weight - I obviously over-estimated a bit. SGS do an "adjustable" strut which has a valve through which you can vent off gas until the pressure is correct for your needs. These might work, but I'd be wary of managing to get the same pressure in each strut - having seen how different struts on each side can distort the roof.
To further complicate a guesstimate for how much gassing the new struts would have needed, was the wear factor on the original struts... A pair of brand new standard struts would have probably worked just fine (if they can still be obtained)
Re: Regassed AFT Struts
Posted: Mon Feb 08, 2010 11:10 pm
by MountainGoat
Ouch! and you did it at this time of the year. Don't tell me that you were weraing your kilt when you did the job Rhod.
Tony

Re: Regassed AFT Struts
Posted: Tue Feb 09, 2010 6:25 pm
by wishmaster
MountainGoat wrote:Ouch! and you did it at this time of the year. Don't tell me that you were weraing your kilt when you did the job Rhod.
Tony

Ohh

I bet it gets a bit cold up there

Re: Regassed AFT Struts
Posted: Tue Feb 09, 2010 7:46 pm
by dandywarhol
It might be cold but certainly nothing worn under the kilt - it should be in perfectly good working order, eh Rhod?

Re: Regassed AFT Struts
Posted: Tue Feb 09, 2010 9:43 pm
by Rhod
So that WAS a mirror on the floor of the Kingshouse bar then Dandy
BDC - SGS can supply a set of struts with the original spec of gas in them. Or they can re-gas your original struts. Not sure how they know what the original spec is though

Apparently re-gassing is a one-way process. They can add gas, but can't remove it

Re: Regassed AFT Struts
Posted: Tue Feb 09, 2010 10:32 pm
by dunslair
Re: Regassed AFT Struts
Posted: Tue Dec 17, 2013 5:05 pm
by llitvack
I wonder if anyone knows how to remove the INNER gas struts for the roof? By this I mean the struts that support the rigid inner liner with the hatch in the middle, on which you can sleep in the AFT. I wanted to have mine re-gassed.
I can speak well of SGS Engineering (referred to above in this thread). I recently bought a pair of adjustable force gas struts from them, for another application on my Bongo (lifting a side-facing sofa), and they work brilliantly!
See
http://www.sgs-engineering.com/gas-struts/adjustable
Cheers from Leon