Roof struts

[chartrock]

Can anyone tell me if there is a right and wrong way to fit the gas struts for raising the roof.

When we bought the van the struts were fitted with the body of the strut fixed to the roof and the moving arm fixed to the top of the van. We had the roof tent replaced under warranty in 2011 but did not notice the struts have been reversed. Now our roof does not lift all the way up in the back corner over the shower and the roof leans to the front of the van, to the point where we cannot open and close the zippered 'windows' at the top.

Obviously my struts are shot but I am unsure if they should have been fitted the other way around and should it make any difference. A walk around a caravan park last week showed every pop top, what ever brand, had the struts mounted with the body attached to the roof

This was taken when we first brought the van home.

This one after roof tent replaced.

 

[Billrw136]

Can anyone tell me if there is a right and wrong way to fit the gas struts for raising the roof.

When we bought the van the struts were fitted with the body of the strut fixed to the roof and the moving arm fixed to the top of the van. We had the roof tent replaced under warranty in 2011 but did not notice the struts have been reversed. Now our roof does not lift all the way up in the back corner over the shower and the roof leans to the front of the van, to the point where we cannot open and close the zippered 'windows' at the top.

Obviously my struts are shot but I am unsure if they should have been fitted the other way around and should it make any difference. A walk around a caravan park last week showed every pop top, what ever brand, had the struts mounted with the body attached to the roof
View attachment 19311
This was taken when we first brought the van home.
View attachment 19312
This one after roof tent replaced.

As far as I can see the strut should be installed with the piston or rod facing down (i.e. body of strut at the top) - this keeps the seal lubricated. So the way they were originally installed on your van, Chartrock, would have been correct.
Incorrect installation would explain premature failure, i.e. the seals dry out.
Do a google search on gas strut installation - heaps of info comes up.
Hope that helps
Bill

 

[Ligedy]

Hi @chartrock

With this type of strut (caravan pop top) - the body of the strut should be installed at the top (shaft end down) to maximise the operating life. Bill is correct in regards to the shaft and seal being kept lubricated this way but it has lots to do with making sure the strut dampens correctly given the forces at play during extension. Incorrect installation will damage the strut prematurely as it won’t dampen the forces properly, as installation and dampening characteristics are dictated by specific strut design.

Hydraulic dampening struts (or gas springs) (have the best price/performance ratio hence are installed just about everything with a heavy lid or hinge) and are designed to be installed body up as they rely on the oil in the gas spring to provide the dampening effect at the end of the extension stroke. If the gas strut was not used rod-down, the piston would not have to go through the oil last, i.e. at the end of the extension, and would not provide the best damping effect thus reducing the lift of the strut.

Did you notice if it opened quicker and harder after the new struts were installed…?

My Expanda is fitted these: http://www.stabilus.com/automotive/lift-o-mat-gas-spring-with-hydraulic-motion-damping/

The comments from the Stabilus website: The hydraulically dampened LIFT-O-MAT has an extra oil chamber. As soon as the piston leaves the gas range and enters the oil, its speed will be reduced. The degree of damping is determined by the use of patented Labyrinth pistons, as well as by the viscosity of the oil. The oil amount used will define the damping range. To dampen extension, the gas spring is installed vertically with the piston rod down. In situations where additional compression damping is needed, there are standard models that can be installed vertically with the piston rod pointing up.

It’s not to say you got upgraded with better struts which dampen during compression as well and are suited for shaft end up installation - but I’m sure you have paid more a little bit more them…

 

[chartrock]

Thanks @Billrw136 and @Ligedy for the replies. What you say definitely makes sense but the struts were not replaced by new ones, the tent portion of the pop top was replaced at the same time as cracks were repaired in he roof under warranty. The struts would have been taken off at this time and refitted so it appears the repairer refitted them the wrong way round. It is booked in on 6th Feb to have them replaced so I may have to have a word with the repairer.

 

[brookes2622]

Hi @chartrock

....

My Expanda is fitted these: http://www.stabilus.com/automotive/lift-o-mat-gas-spring-with-hydraulic-motion-damping/

.....

Hey @Ligedy I am looking to replace my struts with some a little more powerful and these look the goods. You say you replaced yours, did you upgrade to a more powerful strut? Where did you purchase them and what sort of $$$? I know it was a while ago. How are they holding up ... bwha ha ha

Thanks

 

[Ligedy]

Hey @Ligedy I am looking to replace my struts with some a little more powerful and these look the goods. You say you replaced yours, did you upgrade to a more powerful strut? Where did you purchase them and what sort of $$$? I know it was a while ago. How are they holding up ... bwha ha ha

Thanks

Hey @brookes2622 they're holding up just fine... probably because the roof is down more than it is up... not enough holiday's on my calendar :frown:

Sorry but I didn't do an upgrade - those spec''d ones were fitted from the factory. I was just waffling on about which way they are meant to be installed... I did take my struts off to inspect coz my roof is rather heavy and comes down pretty hard, but they packed some punch so didn't go any further. I did post pics of the basic ratchet strap tool on here somewhere else - piece of don't be rude to change out with the right tool...

Cheers, Ligedy

 

[1756mick]

Smaller vans have a 300nm (30kg) strut thereabouts . I know mine has 630nm on the awning side and 600 on the other. The ratchet strap wouldn't even move it one mm. I needed to compress them in a jig with the van jack on the ground and use 5mm metal bars to clamp in a closed position to fit them back in place.