Good Sam Club Open Roads Forum: Truck Campers: Jack Failure Disaster
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silversand

Montreal

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Posted: 04/13/22 06:31am Link  |  Quote  |  Print  |  Notify Moderator

Nice camper by the way! Can't wait to see pics of the final painted shell.

Without doing an on-site forensic, did the legs lower onto a thick mat of long-leaf pine needles (I've slid badly on pine needles in the past)? If the jack's landing pads were lowered onto the teflon-like slippy needles on hard packed ground, they (one landing pad) could have just slipped out (like walking on ice), and caused a cascade of instability with the other pads/legs, and the weak point, the jack attachments, just let go one at a time (even well connected)....Just a thought....

For it not to have sustained major structural shell distortion/damage falling from (near full?) jack extension, that camper must be built like a brick. Looks like a keeper to me.


Silver
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mkirsch

Rochester, NY

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Posted: 04/13/22 06:52am Link  |  Quote  |  Print  |  Notify Moderator

StirCrazy wrote:

BurbMan wrote:

JRscooby wrote:

Unless on level surface, 3 legs is more stable than 4.


Re-read what he said. Hence the reason cameras use tripods, milking stools have 3 legs, etc. Obviously more legs provide more support, but the more legs you have the harder it is to load them all equally. Three legs means each has to carry more weight, but they distribute that weight much easier.


there easier to level and tram with three legs but not more stable, cameras use a tri pod because it would take for ever to get level if you had 4 legs, thankfully we dont need that kinda of persision with our campers


Not necessarily level, but to get it to sit without rocking.

A 3-legged stool will sit stably on just about any surface, but a 4-legged stool will rock on two legs unless you find just the right spot.

Since a camper's legs are independently adjustable, the point is moot.


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JRscooby

Indepmo

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Posted: 04/13/22 10:24am Link  |  Quote  |  Print  |  Notify Moderator

mkirsch wrote:



Since a camper's legs are independently adjustable, the point is moot.


But when you try to lower the load, adjusting 1 jack at a time, it will always be ready to rock on 2

covered wagon

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Posted: 04/13/22 11:06am Link  |  Quote  |  Print  |  Notify Moderator

From the torn off damage it shows the rear jack may have been too short of an attachment point ( not enough Lateral strength) . Is the corner mounting brackets only as long as the damage you can see? My jacks have an upper and a lower mounting bracket giving it more lateral strength.

DanLevitan

NC

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Posted: 04/13/22 07:47pm Link  |  Quote  |  Print  |  Notify Moderator

Yes the rear mounts only had the upper portion. I can see where I would have benefitted from having the lower mounts too. Also check out this picture of the twisted swinging bracket. Its pretty gnarly. It was the front left. The one that peeled off. The left rear then seems to have folded under and doesn't have any twist to it.
[image]

DanLevitan

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Posted: 04/13/22 08:03pm Link  |  Quote  |  Print  |  Notify Moderator

I have an idea of going back to the three wing mounted brackets and modifying an I-beam so I can use the corner jacks in the place of the tripod jacks that would otherwise mount to that type of bracket. I want to keep having a single foot per jack as it seems the tripod feet have to all be on the same plane to keep the jack wanting to move vertical. Also I don't like the idea of the tires contacting the tripod base when backing under the camper. I hope to mock something up during my lunch break tomorrow and will post a picture to get feedback. Going from four jacks to three seems weird but I like the idea of keeping all my jacks seated though-out the procedure and I know that is tricky with four manual jacks. I wish I could afford motorized jacks that would move in unison but that isn't in the cards.

JRscooby

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Posted: 04/14/22 04:19am Link  |  Quote  |  Print  |  Notify Moderator

Maybe think about 5? Front corners, center rear, used until raised/lowered to height, then rear corners to hold?

joerg68

St. Ingbert, Germany

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Posted: 04/14/22 04:57am Link  |  Quote  |  Print  |  Notify Moderator

So one of the front jacks failed first. That is not surprising as they carry more weight. Would it have failed in the same way if the rear jacks had been anchored at the bottom? Maybe, maybe not. In any case the bending loads in the rear get much more evenly distributed that way, and there is much less possibility for flex overall. But the front jacks are still standing free and the mounts need to be able to absorb a lot of bending force. What you did see was that the jack mount tore off the camper structure as it was probably designed to do. Imagine that you snag the jack on a wall or some other obstacle while driving. Then this failure mode will be much easier to repair than if it tore out the complete camper frame with it.

From the first picture posted, it looks like the camper was on fairly level, but soft ground. One of the jacks under load probably started to slide away, not neccessarily the one that tore off.

I have personally watched the third leg of a three legged camper loosing footing on a patch of ice and folding under ... with much the same result. For me, the three-jack design does not inspire more confidence than the four corner jacks.

Some pieces of plywood or similar under the jack feet might have helped, or loading on an even, paved surface. Then again, they might not - I was not there.

We use the electric drill method on our camper as well, but always on a paved surface. One of the rear legs comes off the ground quite frequently in the process, and there is no flex or movement of concern. This happened on the previous campers with electric jacks as well, as the jack motors never have the exact same speed and start to run out of sync eventually.

* This post was edited 04/14/22 05:04am by joerg68 *


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JimK-NY

NY

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Posted: 04/14/22 05:32am Link  |  Quote  |  Print  |  Notify Moderator

Looking at the pictures of the aftermath, it is not clear to me what went wrong. I would consider the following:

Does the camper have suitable structure to support the jacks? Those skimpy wood screws do not point in that direction. My brackets are attached into solid wood with long, heavy lag bolts.

Were the jacks properly aligned at the start? All 4 need to point straight down with no forward-back or side to side canting.

Was the ground really hard and suitable? Did you use support blocks to distribute the weight for the jacks?

Did you jack up the camper keeping the front higher or at least level with the back and distributing the weight as well as possible on all of the jacks? I recommend using levels, front and back, side to side to help with this.

Did the camper and support start on level ground? It looks like there is considerable slope downward to the right and also downward to the back. That would put a lot of pressure on the right rear jack also make it difficult to maintain a level camper with even weight distribution on the jacks.

BurbMan

Indianapolis, IN

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Posted: 04/14/22 07:20am Link  |  Quote  |  Print  |  Notify Moderator

silversand wrote:

Without doing an on-site forensic, did the legs lower onto a thick mat of long-leaf pine needles (I've slid badly on pine needles in the past)? If the jack's landing pads were lowered onto the teflon-like slippy needles on hard packed ground, they (one landing pad) could have just slipped out (like walking on ice), and caused a cascade of instability with the other pads/legs, and the weak point, the jack attachments, just let go one at a time (even well connected)....Just a thought....


joerg68 wrote:

I have personally watched the third leg of a three legged camper loosing footing on a patch of ice and folding under ... with much the same result.


I think the solution is in this line of thinking....it may not have been necessarily a weak jack attaching point but could have been a lack of traction with the jack plate that cause it to slide, placing way too much lateral force on the mounting point and leading to a cascading overload event?

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