Seized electric tongue jack

[Glamper64]

Pretty sure my Husky HB3000 is seized...I can't turn it manually. The RV has been parked for about 6 years so the jack hasn't been used and probably caused the seizure. My question is hopefully not a silly one...I read about brakes on some of these jacks...is there a brake on my model and where is it? What can I do to unseize it...I sprayed a bunch of WD40 through the rubber plug hole...the power to the jack was disconnected so I re-attached it back to the battery...the lights work but no jack...I jumped a ground wire from the negative on the battery to the foot of the jack incase it was an grounding issue but nothing. I just want to raise up the foot to change out a broken pc of wood to a new heavier block. The RV is supported on 4 heavy duty permeant screw jacks. Thanks for any suggestions other than I need a new one

[Markb5900]

If you can’t get it broke free with a socket and ratchet, I would just put a new one on, or get a hydraulic Jack and some boards, Jack the trailer that way.

[jimmoore13]

Changing a tongue jack safely can be a bit of a challenge...first jacking up the tongue with a bottle or other jack and then securing the load on jack stands or other supports.

With that in mind, a working tongue jack allows you to hitch up to your tow vehicle and change the jack with the coupler on the hitch ball.

All that said, it may be worth a bit more effort to free up your current tongue jack to enable an easy, safe swap.

The tongue jack is just a "lead screw"...threaded rod...that spins in the "nut" attached to the top of the hollow tube that extends or retracts to raise and lower the tongue. (Link is just an illustration.)

The "nut" on the hollow tube is probably rusted/frozen to the lead screw.

How to "fix" that. Drill about three holes into the side of the pipe tower on which the motor sits...and that attaches to the tongue/A-frame with (typically) three bolts. Through these holes, spray a good "penetrating oil" style lubricant...don't waste your time with WD-40. Spray this on liberally with the goal of getting plenty of penetrating oil on the lead screw where it engages the nut on the lift/lower tube.

It helps to estimate where the nut might be in its travel up and down the lead screw based on how far the tongue jack is extended.

Let it sit for a while...maybe a day. Gently test with a hand wrench. If no movement, apply more and wait another day.

This may or may not free up the nut on the lead screw. Whether or not it's worth the effort depends on the soil conditions and your equipment available for safely jacking and supporting the tongue while you replace the jack, If you have a good jack, jack stands, and blocking to support all that on "soil", just buy a new jack. It only takes removing 3 bolts and one wire. But if your conditions and equipment are sketchy, you might try the penetrating oil so you can change the tongue jack with the hitch on your hitch ball.

BTW, if somehow you actually salvage the tongue jack and keep using it, you can cover the holes in the jack tower with a couple of wraps of electrical tape to keep the crud out.

[Glamper64]

Thanks Mark and Jim, appreciate it. I think I'll drill some holes and spray a lot of penetrating oil...I'm assuming I should drill those holes at the top, middle and bottom of that pipe tower or do you mean three holes around the top of that pipe just under the motor?

[JFlightRisk]

Probably best just under the motor, on the upper tube. Maybe wrap an old rag around the lower tube under the tongue to absorb any penetrant that leaks down. This may work, at least it's worth a try.

[Glamper64]

Thanks, I'll give it a try next week and let you know how it went.

[jimmoore13]

Originally Posted by Glamper64

Thanks Mark and Jim, appreciate it. I think I'll drill some holes and spray a lot of penetrating oil...I'm assuming I should drill those holes at the top, middle and bottom of that pipe tower or do you mean three holes around the top of that pipe just under the motor?

You want two holes above the Nut on the lift/lower tube. The one at the very top enables you to shoot penetrating oil up onto the underside of the top bearing/bushing carrying the lead screw in the jack tower. The one in the middle enables you to slather lots of penetrating oil on the lift/lower nut on the lead screw. Try to estimate the location of the nut based on your memory of how far the jack extends, and guess where the nut is...and drill the middle hole above the nut. This will allow the penetrating oil to ooze its way down the lead screw to the nut.

You need the hole at the bottom, because the lead screw is retained at the bottom with a "bearing" (likely a bushing) that might also be frozen a bit.

I neglected to mention that you should remove the jack cover...or pull the manual override plug...and slather the upper bearing for the lead screw with penetrating oil. Apply generously at all locations.

I like JFlightRisk's suggestion to catch the runoff oil with rags...perhaps wrapped around the lift/lower tube. Penetrating oil often stinks like hell, and it's best to never contaminate the ground with petroleum products. Be careful with the rags. DO NOT put them in a closed container or zip-loc bag. When contained, they can spontaneously combust. Oil saturated rags can be safely stored until the next trash pickup by just leaving them in an open top container outside.

Again...the right answer to your problem is a new jack. All this monkey motion is aimed at enabling you to drop the coupler on your hitch ball to easily and safely change out the jack.

[Glamper64]

Well after a couple days of spraying penetrating oil holes into holes drilled in the jack tube, I managed to unseize my tongue jack...it did take a lot of pushing and pulling then it finally started moving the broke free. So I was able to raise the RV, brace it to make it perfectly level and change out the rotten pc of wood under the foot. The jack worked really nice/smooth up and down when it was under no weight...then I installed the new 6"x6" block with a 2"x8" base screwed on it and started cranking it up...when it started pushing on the new block I could feel it slipping/loose then it would grab but it was winding up with tension as I cranked...if I let it go it would unwind violently...I thought it was broken for sure. So I try again and cranked it up to where I wanted it and (stupidly I thought after) wedged a small garden shovel into the propane tank handle to hold it in place while I adjusted up the two temporary and two permanent jacks. To my surprise and delight, when I released the shovel holding the bar it didn't unwind and held its position, weird. What would cause that? I'm thinking it was too much penetrating oil Here's some more sideways pics.

[jimmoore13]

Please replace it. I confess that I don't understand the "braking mechanism" in a tongue jack (if any), but "something" has to hold the jack from unwinding in this manner. From my POV, the reason to free up the jack was to avoid the monkey motion of separate jacks and jack stands. Since you are now well supported, I urge you to get a new one. And there is no such thing as "too much lube" on a lead screw and nut...and lead screw shaft bearings/bushings.

The tongue jack carries the entire weight of the tongue when setting up your rig on site...or parking it. Were it to unwind while staged on the stabilizer jacks, it would ruin them, put your camper far out of level, and if you are setup on a side hill and not really well chocked off at your axles, your rig could pivot and careen downhill into a tree, picnic table, nextdoor camper, or a person. My sense is that this is no longer safe to use.

Best of luck.

[Glamper64]

Thanks for your concern Jim. My permanently parked RV is scissor chocked and well supported on four HD jack stands on patio stones. The stabilizer jacks are snug and stabilizing, not carrying any weight. I'll keep an eye on my tongue jack and will replace it with a new manual one if it becomes loose or unwinds.

[Glamper64]

I'm posting these pics right side up this time in hopes of some more responses on why my jack did what it did in post 8. Maybe at least a "risky but good job Glamper"

[Jaykol]

A incorrectly spec'd lead screw can back drive (lower under weight), but a properly spec'd one can not. It is the ratio of diameter and thread pitch. No idea what is used in a jack but if done correctly they would not need a brake. I would agree with others to change it out before something bad happens and keep backup support under the tongue in the meantime.

[Glamper64]

I probably will change it to a manual one because it's parked permanently, thanks. We're heading up there next week Thursday for the long weekend, I'll check it out then...if the jack is still tight it will be three weeks...I may leave it for now...mind you, it would be a fun easy not to expensive project and piece of mind

[Glamper64]

Just following up on my own thread again The unseized jack was still very tight after a few weeks now following the winding up incident I'm going to leave it for now...there's been no unwinding and with the HD jacks in place as well as the stabilizers jacks, I'm not worried. Thanks again...the drilling holes and penetrating oil thing did indeed work

[jimmoore13]

Originally Posted by Glamper64

Just following up on my own thread again The unseized jack was still very tight after a few weeks now following the winding up incident I'm going to leave it for now...there's been no unwinding and with the HD jacks in place as well as the stabilizers jacks, I'm not worried. Thanks again...the drilling holes and penetrating oil thing did indeed work

Glad to hear it.

I used drilling holes and lubing (with conventional spray silicone) on a manual tongue jack that was getting increasingly "tight" years ago.

I'll do the same for my current electric tongue jack before next season. The manufacturer's jack failed 2 years into ownership, and I was able to use the manual override (drill and socket) to get home. Left the rig on the hitch, ran down to a local RV store and got a replacement. So my new jack has only seen two seasons, but I will lube it ... perhaps before I put it to bed for the winter.

The lube is also protective against corrosion, and, as we all know, in humid conditions, air trapped in a gas tank or tongue jack column will condense out water when the temps fluctuate. The "oil" on the lead screw, bearings/bushings, and nut will keep that water from rusting the moving parts.

PS, I don't bother with "covering" the small holes on the lee side of the jack. I doubt any contaminants will find their way into these tiny holes.

[Glamper64]

Thanks Jim, I'm confident about the jack holding and it should be well lubed up for the winter, spring and summer I'm not worried about the holes in the tube either, actually they're fantastic for future lube jobs and act as little breather holes to reduce moisture year round