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Gas struts coming undone

PostPosted: Sat Nov 15, 2014 7:08 pm
by olive
Anybody know what causes the hydraulic struts to come undone from their mounts on the hatch?

These struts work just great but often the socket end pops off the ball mount on the hatch. This will happen either when opening the hatch or closing it. These are LaVanture struts that only come with ball and socket ends.

Thanks in advance with any thoughts.

Re: Gas struts coming undone

PostPosted: Sat Nov 15, 2014 8:20 pm
by noseoil
Not familiar with the exact brand, but usually there's a bent "wire clip" which acts as a positive locking mechanism. Does the socket part have a very small hole drilled in the edge where the ball slips in? If so, usually a wire clip keeps the ball from popping out.

Re: Gas struts coming undone

PostPosted: Sun Nov 16, 2014 3:40 am
by working on it
olive wrote:Anybody know what causes the hydraulic struts to come undone from their mounts on the hatch?
These struts work just great but often the socket end pops off the ball mount on the hatch. This will happen either when opening the hatch or closing it. These are LaVanture struts that only come with ball and socket ends.
If these are your fittings,
laventure end,clip.GIF
laventure end,clip.GIF (42.97 KiB) Viewed 1413 times
then you maybe missing the integral clip, or it may have lost its "spring tension". But, if you have this type ball end This is what I use, and noseoil is referring to
clip(example2).GIF
clip(example2).GIF (50.2 KiB) Viewed 1413 times
noseoil wrote:Not familiar with the exact brand, but usually there's a bent "wire clip" which acts as a positive locking mechanism. Does the socket part have a very small hole drilled in the edge where the ball slips in? If so, usually a wire clip keeps the ball from popping out.

Re: Gas struts coming undone

PostPosted: Sun Nov 16, 2014 6:45 pm
by olive
Thanks for the replies but....the internal keeper spring LaVanture uses is in place. The springs might be weakened but I suspect there might be something else going on since the end brackets are bent.

Re: Gas struts coming undone

PostPosted: Sun Nov 16, 2014 8:11 pm
by High Camp Trailers
Sounds like the strut is exceeding the plane that the ball mount and strut was intended to operate on. The ball mount only allows a certain amount of rotation around it. Kind of like separating your shoulder by over extending your arm up. Just another possibility. Otherwise, maybe a loose clip which should be easy to switch out. Try liftsupportsdepot.com for parts...
Good luck,
Dennis

Re: Gas struts coming undone

PostPosted: Mon Nov 17, 2014 12:39 pm
by olive
Hmmmm....awaiting a reply from LaVanture regarding the issue. May be easier to change out the struts but this time use an eyelet end versus the ball and socket. The suggested liftsupportdepot site seems to have everything....thanks.

Re: Gas struts coming undone

PostPosted: Tue Nov 18, 2014 6:28 am
by noseoil
"....but I suspect there might be something else going on since the end brackets are bent." If the brackets are bent (pictures?) then it sounds like the weight loaded onto the bracket from the gas spring is what's causing the trouble. The springs may be good still, but if the brackets are out of alignment and the balls are popping out of their sockets, then some heavier brackets might be in order to fix it.

Olive, can you post a couple of images of the bad parts & their alignment? That would help us a lot, to understand the problem better and make better guesses at a solution.

Re: Gas struts coming undone

PostPosted: Tue Nov 18, 2014 2:49 pm
by olive
Whoppin' 10 degrees out there this morning!

Having never posted images...here goes. This should be the lower mount: Image

The upper mount: Image

And finally the extended strut: Image

Here's my latest guess what's going on. First let me say these struts are 20" long when extended with 8" extension; they exert 120 pounds of lift. When the hatch is closed and the struts are collapsed their horizontal plane is about 45 degrees above horizontal. With the hatch open and the struts extended their horizontal plane is about 60 degrees above horizontal. My guess is that that 120 pounds of pressure is pushing more on those mounts - horizontally - than pushing up the hatch - vertically. Therefore the struts blow off the mounts when either opening or closing the hatch. If I'm correct the mounts need to be relocated so that the struts do more pushing the hatch up rather than pushing the mounts horizontally. To do this correctly will take new longer struts to get the hatch high enough.

My proposed cheap fix is to change the strut ends and mounts to eyelets so they can't pop off the mounts since the system works as currently set up....other than popping off the mounts.

Whew!

Re: Gas struts coming undone

PostPosted: Tue Nov 18, 2014 10:19 pm
by noseoil
It sounds like you have the right idea. If the ends are mounted with eyes instead of a ball & socket joint, there can't be an alignment problem. Make sure the attachment bracket is strong enough to stand up to the loading & the fasteners are adequate.

Is the hatch fairly heavy? Is 120# overkill for the strut, or is that just what it needs to keep the hatch in place? If you change struts & length, the geometry will be different & you will need to re-vamp attachments on the side panel & hatch. Not always easy to find a "hard point" to fasten to, due to some fairly heavy loads involved and having enough structure to fasten to. Keep us posted on what happens.

Re: Gas struts coming undone

PostPosted: Thu Nov 20, 2014 1:27 pm
by Sheddie
Hi Olive,
Have you checked how far the strut is compressed when the hatch is closed? Set your camera on auto sit it on the bench aimed at the bottom mount and shut the hatch and post that photo.
:beer: Frank.

Re: Gas struts coming undone

PostPosted: Thu Nov 20, 2014 3:48 pm
by migal0412
A quick and easy way to check your correct placement of brackets. Support your hatch in the open position and unclip the bottom attachment and let the struts hang freely. With the strut fully extended take a pencil and line up exactly the centre of the bottom cup end and by swinging the strut and pencil describe an arc on the side wall the tear. Your bracket ball should be fastened precisely on this arc, if it is not then often problems such as you describe can occur.
I hope you get the idea.
Cheers Mike

Re: Gas struts coming undone

PostPosted: Fri Nov 21, 2014 4:16 am
by Sheddie
Mikes method for finding the position for the extended strut with the hatch open will work fine, if you have a restricted upward amount of travel on the hinges. But, what you need to check is the mounting position for the compressed strut with the hatch shut. What I am thinking is that the strut is reaching full compression just before the hatch is fully shut, and if this is the case it will be the cause of the bent mountings and putting a lot of extra load on the ball sockets.
:beer: Frank

Re: Gas struts coming undone

PostPosted: Fri Nov 21, 2014 7:29 am
by noseoil
What they said... From reading about the various layout techniques on strut mounting (and related problems), it's a good idea to use the "shortest length" (compressed strut length) which is actually 1/4" or 3/8" longer than the specified length from the manufacturer. That way, there's no possibility of having the compressed length be a bit too long & pranging the brackets at full closure. A smaller amount than 1/4" is fine, but if it's bottoming out at the closed position, there will be problems with fasteners, brackets or the hinge sooner or later.

Not sure if this is what happened here, but if you start looking at doing a different layout and moving things around, leave a bit of extra length for the "closed" hatch position strut length, to make sure there can't be a problem when the hatch is fully closed.

Re: Gas struts coming undone

PostPosted: Fri Nov 21, 2014 8:01 am
by angib
Sheddie wrote:Have you checked how far the strut is compressed when the hatch is closed?

This does sound like it could be the problem - trying to 'overcompress' the strut would produce enough force to start breaking things.

Another technique to check for the extent of movement is to extend the strut and put a zip-tie round the rod - how far the zip-tie is pushed up the rod shows how far the strut closes.

Re: Gas struts coming undone

PostPosted: Fri Nov 21, 2014 11:44 am
by olive
What a great discussion.

I don't think the struts are over compressed but I'll be able to check further after the parts I've ordered arrive. I marked the side of the TD at the point where the upper mount comes to rest with the hatch closed. I then marked the side of the TD at a point 12" from this first mark which should align with the lower mount since these struts are 12" when compressed. This second mark aligned with the lower mount. Don't think it's an over-compression issue but standby for my report once the parts arrive!