# Scissor Jack Problem - Won't Stay Down



## NonTypicalCPA (Apr 16, 2011)

Not sure why but one of my scissor jacks on my '09 250RS won't stay down and support the trailer. I crank it down with a cordless drill (not leveling, just for support) but any weight or movement of the trailer and the jack raises all by itself. This is a new trailer to me and after its maiden voyage this past weekend I noticed the trailer developed quite a bit of movement. When inspecting the jacks, this one was 2 inches off the ground - just from normal use of the trailer over a few days. When I got home and cranked it down again, I noticed it collapsed (raised) to the point of the wheels taking the load of the trailer. I could easily turn the nut with just two fingers to raise it. What's going on here? Any solutions short of replacing it?


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## thefulminator (Aug 8, 2007)

It sounds like you have either lost or cracked a part on the main screw somewhere. These jacks require a certain amount of friction to not just unscrew on their own. For some reason you have lost that friction. Take a good look at one of the jacks that works and compare to the bad one. Can you see any parts missing? Also, the jacks aren't really supposed to take weight off of the wheel but are there just to stabilize the trailer. It's kind of like walking with a cane. The cane steadies you but isn't supposed to hold your weight.


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## duggy (Mar 17, 2010)

I think the physics of the screw going through the jack, say that no matter how lubricated it was, it could never push up and make the threaded rod turn. There must be something broken in the jack. The only other explanation could be soft ground, but you said it did it at home as well.

To prove that it won't vibrate up, think about the fact that you drive hundreds of miles, and the jacks don't fall down.


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## thefulminator (Aug 8, 2007)

That was my point. Just the friction of the screw mechanism keeps the jack from dropping during travel. When there is weight on it, the friction force increases so the jack doesn't contract. There is something mechanically wrong with the screw mechanism. Something is broken or missing.


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## vdub (Jun 19, 2004)

On the part of the jack that is closest to your screw nut, there is a donut around the screw. The donut is secured in place by spring pins on either side. I suspect the spring pin closest to the screw nut is missing or broken. It's a simple fix. You don't actually need to replace it with a spring pin. I have replaced mine with soft rods (actually, the hang up thingies for peg board) with good success -- yeah, it was a weak moment, but I was desperate. Several thousand miles and it's still good.


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## rdvholtwood (Sep 18, 2008)

I have an '09 250RS and noticed that at times too. I, like you, use a cordless drill with the torque set low so that I don't end up lifting the trailer after the jack is fully extended. I've notice that with my drill torque set like this that after being in the TT for awhile I will find the jacks loose. What I have been doing is after I use the drill I go around and hand snug the stabilizers with the stabilizer wrench. This seems to have been working for me.


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## NonTypicalCPA (Apr 16, 2011)

Thanks everyone. I'll have to inspect them more closely to see if I can see a broken or missing part. I didn't notice the problem with any of the others so my guess is that there is something wrong with it. I did have my cordless drill clutch set to a low setting, but I would have thought the other jacks would have the same problem. Definately not soft ground, I was on my paved driveway.

FYI I'm not lifting the weight off the tires, it was just the best way I could explain what I was experiencing.

I'll report back what I find.


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