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Happijac lubrication

KKELLER14K
Explorer II
Explorer II
Thanks to the new Chrome extension, the pics are back! You must view in Chrome with the extention. Here is the link: https://chrome.google.com/webstore/detail/photobucket-embedded-imag/ogipgokcopooepeipngiikdkpmcpkaon... .. It has been a misconception even on my part, that adding machine oil to the crank socket lubricates the jack itself. This is UNTRUE! I now have a complete tear down with pics to show everyone what goes on inside and how to disassemble and lube the working parts if need be. This is a little lengthy but most will find the education worth the read. This is a model 4150.

First you have to make a little tool like this. An old hanger works good. This will serve two purposes, explanations following.

Remove the two screws that hold on the motor.

Pull the motor off the jack.

Pull out the spring loaded socket.


Remove the lever and pin...a pair of flush wire cutters works well. Wedge them underneath and they pop right out.


Remove the internal plastic manual mechanism...note how this is installed. one side has a round hole and the other an oval shape where the lever goes.



There is a "C" clip here, you need to remove it with the little tool you made. Just put it in from the side and pull back. It will pop right out.


Once you get the clip off then pull out the manual socket.


This is the hole in the socket that is to be oiled, but as you can see in the next few pics, the only thing that is being lubed is the socket itself.

Once you pull out the socket, remove the manual gear.

Now as you can see the oil really goes nowhere. There is actually a lot of grease here. What your going to do next is pull this gear off that shaft straight towards you. Use that tool again to hook the gear from behind and pull it. You may have to do it a few times, the shaft gets a little burr on it but if it gets stuck ,just push it down and keep yanking, it will come off!

Once the gear comes off, this is what the back looks like. It has two slots. The slot that has the closed ends is what holds the pin in place. IT IS IMPORTANT YOU PUT THIS BACK TOGETHER THE WAY IT COMES APART!

Rotate the shaft so the pin is facing towards the corner and pull it out.

Now pull the leg assembly out of the jack housing.

Get ready to inspect and re lube.






Pull this cinch spring off and inspect this bearing.


Use an air ratchet or drill to turn the worm screw all the way out, inspect and re lube.

Re-assembly is just the opposite of the tear down. I found that even though this jack was sticking on me, it was still pretty well lubed, but maybe not enough.....Hope this dispels any unknown facts as to how these things work. One other note is that if the worm drive of the leg was to wear out...seems like you should be able to replace it rather than the whole jack. MMMMMM...haven't got to that yet but I wonder if they sell it seperatly? Does any one know?
225 REPLIES 225

canudad
Explorer
Explorer
Excellent post. I bought a secondhand truck camper with these jacks. The previous owner had printed this post and put it with the documentation. I just spent a full day cleaning the dirty grease out of one. A previous owner had put grease fittings on it. Seems like a good idea but grease gathers dirt and sand. It is like trying to clean a square closed breach cannon. No fun. Since the Happijac doesn’t have any scrapers the dirt gets pulled up between the square tubes and jams them up. The Happijac instructions say to use car wax. I suspect any dry lube would be ok. If you use grease be sure to clean the inner tube before retracting.
I guess another option would be to put fittings near the top on all 4 sides and force enough grease through to force out the grime.

devildog1971
Explorer
Explorer
I have the happy jacks with the motor on top not the side
2019 Northern Lite 10-2 EXCDSE Dry Bath 2007 G M C dually crew cab and 2018 Harley Davidson Limited Low

Artum_Snowbird
Explorer
Explorer
Most likely you have examined the suspect stuck jack with a good straightedge, but using a four foot level might indicate a tiny bend in the tube.

You could certainly try putting the tube into a clamped holder, and apply a minimal amount of pressure with a hydraulic jack while you attempt to move it. If you do manage to move it then, at least you will know which way the bend might be.
Mike
2012 Winnebago Impulse Silver 26QP
2005 16.6 Double Eagle
2018 Jeep Wrangler JK
previously Snowbird Campers,
Triple E Motorhome and Fifth Wheel

goshawk
Explorer
Explorer
Cannon, you could be right. I bought the camper used with the jacks on it. Previous owner did indeed back into something, damaging the mounting plate on the back corner of the camper -- fixing that corner is one of the jobs on my list.

On the other hand, 3 of the jacks work fine, and the jack in question was on the front right side, which shows no sign of damage. And I can't detect any deflection in the stuck jack. But yes, with tolerances so tight, that could certainly be the problem. And previous owner might have swapped it around.

Glad to hear JimK got 18 years out of his. That would do me.

Cannon_George
Explorer
Explorer
Goshawk
Regarding Exterior Finish: (for others) - there was a period of time where Happijac tubes were rusting badly via small exterior corrosion cells, I believe due to bad coating, I had to disassemble the jacks and take the tubes in to be sandblasted and powder coated. This fixed the problem. I wrote to Happijac but they did not answer me.

Regarding Bound-up tubes: I'm sorry for your trouble. Need to ask, is this just one tube or all 4? Is it at all possible you backed into/hit something and may have bent the tube(s)? (It wouldn't take much deflection to mess this up).

Regarding motors and water entry: It supposedly never rains in So Cal but I've had to rebuild several motors for this. Can't explain why, but motors were seized up solid with clear signs of water entry and damage. FYI, the little "drill motor" size bearings were readily available on Amazon for as low as 10qty/$12.99; (Same size as used in kid's "spinners") - the local NAPA store wanted $70 for just one bearing! It is my experience that years ago you could send in motors for exchange/rebuild but nowadays they will only sell you a complete replacement motorhead assembly, no exchange possible.

I'm overall happy with Happijac; but I'd be happy paying a little more for some extra Zerk grease nipples or oil lubrication ports, if that would assure longer life/ease of maintenance.

JimK-NY
Explorer II
Explorer II
Several years ago I was about ready to take an extended trip. I went to put the camper on the truck and one of the Happijacs was stuck. It would not work with the motor or the manual crank. I took it off the truck and still could not get it to work. I had to buy a new one. In fact I bought 2 just in case I have this happen again. Considering they lasted 18 years I don't feel too bad. I am more upset that I lost 2 motors because the seals leaked and they got wet.

goshawk
Explorer
Explorer
Update: still stuck, but I've learned a couple things. With the gears removed, at the point where the inner tube should slip out of the outer tube (but mine doesn't) I find I can turn the shaft easily. Smooth and nice. I figure that means the inner mechanism, the worm drive and all, is in good shape.

Because it's no longer held in place at the top (and no longer trying to move the stuck inner tube) I can crank it down about an inch, so there's free space between the top of the inner worm drive mechanism and the welded plate that serves as a stop when everything is properly assembled. Which in turn means that I can tap on the foot end and move the inner tube upwards about an inch. Then crank at the top again, make room, tap at the bottom... and so on, gradually compressing the whole rig, pouring in penetrating oil as I go. I'm hoping to free it up with the movement and the oil.

So: I can move it in, but can't pull it out. I'm thinking of trying a come-along on the pulling end if it stays stubborn. Maybe donate it to a tractor-pulling competition, LOL

For what it's worth, the inner tube -- the 30 inches or so that I've had out -- is clean, smooth, in good shape, no rust. That outer tube must be a mess inside.

KKELLER14K
Explorer II
Explorer II
My fix? They need to dip the outer tube and coat that tube with a layer of galvanization and the foot to. Do yo know that they put 4 small plastic discs at the bottom of the tube? I know that this can scrape off the paint from the leg and bind it up when a lot of pressure is leaning to one side...another fail.

54suds
Explorer
Explorer
Ill say it they've been producing junk for years its about time they repair some at no charge look at their history of so called improvements all of which only raised their prices and barely improved quality
2021 Chev 6.6 duramax ltz DBL cab,drw,4x/torklift tdn's,
1999 Bigfoot 1011

650cent
Explorer
Explorer
I've heard Happijack has a fast turn around time, why not send it back to them?

Bert_the_Welder
Explorer II
Explorer II
Those with experience with them:
Would waxing the legs help?
Or shooting them with silicone type sprays?
Having a cover for the motor head units while stored, if outside?
To be honest, I'm a bit nervous/surprise at some of the experiences posted here. Certainly sound like these units need to be babied right from day one.
:h 1998 GMC 2500, 10.5 Okanagan, My better/smarter half, George and Finnegan(APBT), all I need.

KKELLER14K
Explorer II
Explorer II
It has got to be really rusted up....that square plate has to slide out from the head. Just keep working it!

ticki2
Explorer
Explorer
A 50/50 mix of acetone and ATF makes an excellent penetrating oil . Turn the jack upside down and let it soak at lest a few hours , overnight is even better .
'68 Avion C-11
'02 GMC DRW D/A flatbed

KKELLER14K
Explorer II
Explorer II
Keep on it, don't give up you will get it apart. Once you do you will be happy you did. If you got the gears off the top, it will come apart. If you can't get the upper gear off, use some sand paper to take the burrs off the shaft. Mine got stuck first try but I finally got it apart. Sounds like you have a lot of junk inside the tube. Can you imagine how hard the motor is working to get the leg down?Good luck and repost what you find.