Following on from a recent thread I've been giving this some thought because I'm that sad. I've come across three people in recent months who have suffered with Cracked front and rear panels on their vans. All three people had caravans with extended front and rear panels. By extended, I am referring to the fact that the plastic front and rear panels extended beyond the vertical line of the van and a reasonable distance along the roof.
My theory is this: A box (the caravan) with a flexible base (the chassis) travelling along uneven surface (the road) needs to be flexible in nature.
A relatively straight forwards (older fashioned caravan) four sided, with a generally flexible roof and wet relatively loosely connected joints would probably achieve this quite well.
If you take away the flexible nature of the box by extending any of the side sections of the box (front and rear panels) up and over angle and onto the roof for a reasonable distance, you will undoubtedly reduce the flexibility of the unit. By doing this the joints wont be able to do the flexing anywhere near as much.
What you might see then, is the need of the front and rear panels to flex much more or, to compensate for the lack of flex in the general design of the box.
All three people I've spoken to had vans with such a design, two of the breaks have been close to or on the points where the panels are attached to the side sections. Which could support my theory.
I'm not saying this is the reason for all plastic panel cracks, just that there has to be much more flex in the older fashioned designs and this might be a contributing factor to cracks in some models.
It's a bit like the bridge scenario, if you make it less flexible through materials, joints or shape, it could break trying to flex. Too flexible and the thing can shake apart, the trick is to get it just right.
Have designs, materials or joints become too inflexible?
Hi Tony B, All caravans will flex to some degree, as the van body is bolted to the chassis in at least 6 places, 4 of them usually at corner steadies, and near the wheels, if the chassis flexes because of the over hang each side of the axel, you will get flexing in the van body at the extreme ends of the body, as well as the roof above the wheels, ( it maybe the cause of vans needing to be re sealed, pulling and compression of all the van joints), I would have thought that older were as susceptible to flexing just the same as the new ones, new ones probably more so if there is a longer distance from the wheel to the ends of van, the bigger the distance the more it will flex, a contributing factor could be, the weight of end kitchens, bath rooms, bed rooms, that maybe another points to consider in your theory.
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Fair point JHSW, not really considered the weighting and location of heavy kit inside increasing to the amount a van has to flex and increasing the chances of panels cracking.
Still though, suspect strongly that some of the newer deigned panel reaches detract from the flexibility of the shape, therefore increasing the flexing that the panel needs to do.
Could be combinations of things. I suspect the last few winters, and the really bad state of some of the roads doesn't help any.
I also wonder if some of the new techniques of joining panels allow either enough movement of too much in some cases?
You may have a point I can see your meaning and string of thought but in my case the cracks were on the joint above the front window which is a full window across the front unlike the traditional three windows across the front of the van and from what I can gather Bailey have admitted that it was a design fault.They have changed the design and made changes but that didn't help me,my van is 2004 Bailey Ranger but its all water under the bridge now and all has been repared now, not sure which make of van you are refuring too.Ian
Someone I know has a late 90s Lunar which has a crack in the front panel. He drilled the end of the crack, to stop it spreading, but still it grew. He took it to a caravan workshop where they told him the front panel had come away from the floor, the resulting loads were too much for the panel to bear & it was cracking under the strain.
I found this out a few months ago & it all made perfect sense then, but I've forgotten the details, except it was apparently a known fault with them.
Possibly something to look out for???
I know what you mean about movement though. I used to be in the building trade, my first job was restoring listed buildings, where I often saw times where people used modern materials, which don't move much at all, on old buildings, which move quite a lot.
All structures like to move. I often think about my little Lunar, with it's highly flexible aluminium side panels & the increasingly brittle, ageing GRP end & roof panels. So far the only water ingress I've found is around the side windows (& a little by the door, where two panels overlap). The ends & roof seem fine (touch wood).
How many people,including myself,leans on the body work to clean it.Ive seen myself leaning on the cover of the "A"frame to get up and heard a crack and then seen a hairline fracture line.
it is a known fact 2004 2005 2006 and before these dates the panels were suspect on many caravans.most of the cracks appeared where the front panel joined the roof,front and back.avondale imho went bust because of it.the makers of the panels also fell to the wall.i think the poorly fitting panels and the stress factor caused the cracks.the panels are now made by below .unballanced wheels can add to the shaking of the body.pulling and pushing on the handles does not help (i try to avoid this) because all the panel is flexed each time this is done and if its stressed something has to give.i shut my eyes when our large friendly warden says can we take it off and push it back onto the pitch.just my opinion mind.type in (cracks) in search and lots come up.
Another problem is that of pulling on the caravan handles. I think the advice is always to push on them to move the van. Even so, this is still bound to cause some stress. Perhaps those who use their mover for all movements of the van may assist a reduction in the risk of such cracks. However, the greatest amount of stresses that force the van to flex must be those produced by the varying conditions of road surfaces.
Because caravan designs change almost yearly, including the basic shells, I doubt whether any long-term investigation has been carried out to establish the true cause of cracking. Also, if cracking occurs after expiration of the warranty, and beyond a "respectable" length of time, are the manufacturers likely to be particularly concerned about such faults?
it is a known fact 2004 2005 2006 and before these dates the panels were suspect on many caravans.most of the cracks appeared where the front panel joined the roof,front and back.avondale imho went bust because of it.the makers of the panels also fell to the wall.i think the poorly fitting panels and the stress factor caused the cracks.the panels are now made by below .unballanced wheels can add to the shaking of the body.pulling and pushing on the handles does not help (i try to avoid this) because all the panel is flexed each time this is done and if its stressed something has to give.i shut my eyes when our large friendly warden says can we take it off and push it back onto the pitch.just my opinion mind.type in (cracks) in search and lots come up.
right you are john.and less chance of a heart attack pushing one and a quarter ton round a corner.Zafiral thats a new one,must remember that,did the bonding sealant fail or the overlapping?
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Sorry not going to pull any punches here with vans being much heavier and modern materials being a vast improvement on old I believe it to be poor manufacture & design by companies that don;t give a damn about their customers. With new vans costing anything from 15,000 to over 20,000 where else would you except the amount of structural failure that seems to be rife in the industry
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Topic: Theory for Cracked Panels.
