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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

What is everyone living the acme screw with?

Bert_the_Welder
Explorer II
Explorer II
Geezus.....my new TC has Unhappijacks. This thread is pretty alarming..... Sounds like they are only meant to be used indoors.....
:h 1998 GMC 2500, 10.5 Okanagan, My better/smarter half, George and Finnegan(APBT), all I need.

goshawk
Explorer
Explorer
Thanks Draggin! I will patiently continue. It's good to know that I've got the concept correct.

JS

dragginbaet
Explorer
Explorer
I had the same experience. The likely reason is the tubes are stuck is because there is a build up of rust and grit between both tubes. You are on the right track; it's a slow process. Try using a better quality penetrating oil applied from the bottom. Stand the jack upside down for hours. You may have to repeat this several times before you get results. I separated the pieces using two techniques (the trick is you don't want to hammer pieces so hard as to cause damage). 1) I locked the jack in a vise and tapped the foot of the jack to get some movement. 2) With all the gears removed you'll notice a hole at the top end. I used a piece of rebar about 1 1/2 times the length of the jack and tapped it against the inside of the foot. Once thngs start moving the effort required will decrease. Before reassembly I cleaned the tubes with acetone and steel wool. Upon reassembly I greased the running surfaces of both tubes (it's messy). The root of the problem is that the recommended lubrication method is not effective. Little to no oil gets into the tube area and over time moisture and road dust causes gunk inside the tube. Happijac owners are left with no joice but to disassemble the jacks every 2-3 years to clean and lube the tubes.

goshawk
Explorer
Explorer
Seems this is a perennial topic, and I'm the newest one in need of help. Thanks to KKeller's photos, and the pdfs, I've almost gotten my sticking stubborn jack disassembled.

Where I'm stuck is getting the inner tube out of the outer one. After taking apart everything at the top of the jack (gears, etc) I tried to pull that inner tube (the black one with the foot on it just to be clear) out of the outer tube. Totally stuck.

So I re-assembled and put the jack back on the camper and cranked it as far out as I could. Not easy, but it still functions with enough elbow grease on the manual crank. I hoped that getting it most of the way out, I would be able to pull it the rest of the way.

So I took it off the camper, disassembled it again, and have tried all the tricks I can think of to pull the two pieces apart. No success. I can't budge it a hair. Lots of WD40, lots of tapping on the tubes. Something is fiercely stuck.

Am I missing something? Something I need to remove before I can get these things apart? I hate the though of buying new ones because I can't maintain the old ones.

Cheers,

JS

Ripit
Explorer
Explorer
Thanks. This was very easy and helpful. Didn’t take long to take apart clean and lube and put back together. Warning, the plastic cap opposite the switch broke when I was disassembling. I found a nylon bushing at the hardware store that will work to replace that. There is a 1 5/16” rubber o-ring on top of the leg. Mine had tore apart. I’m not sure where it belongs but I looks like it fits into a groove on the top of the leg. Maybe for a bump stop when the leg is all the way in the up position. Other than that all went well. I found son bevel gears on etrailer and wiring junction boxes at Lippert Componets Lci1.com if anyone is needing these items. Good luck.
2017 F-250 Super Duty Crew Cab
2007 Outfitter Apex 8 Loaded
2014 Eastcape Lostman
2004 King Cat 296

TCs_a_lot
Explorer
Explorer
Came off of a 2006 Arctic Fox, HJ 4500.

54suds
Explorer
Explorer
how old, model/# Crapi Jack
2021 Chev 6.6 duramax ltz DBL cab,drw,4x/torklift tdn's,
1999 Bigfoot 1011

TCs_a_lot
Explorer
Explorer
Thanks a lot for posting/saving these pics. I recently had an inner tube drop out of a HJ lift while my camper was on my truck. This disassembly was critical. I was able to determine that a torsion pin had failed! I was able to replace it and reassembled the jack.

Don't usually reply to forums like this, but thanks.

Blk88GT
Explorer
Explorer
I just wanted to say thank you to everyone who's contributed in here. One of my jacks locked up on me and I was dreading having to source a new one. With the help of this thread I brought it back to life and it's never worked so good. I found a large amount of rust/corrosion inside that the previous owner neglected to service. Instead, the dealer soaked him for ~500 for a new motor.

AnEv942
Nomad
Nomad
One of the pdf files identifies o-ring and lists sizes (if correct model)
01 Ford F250 4x4 DRW Diesel, 01 Elkhorn 9U
Our camper projects page http://www.ourelkhorn.itgo.com

dragginbaet
Explorer
Explorer
Thanks for sharing your Happijack experiences. My jacks have given me grief for a few years; really noisy, non-sychronized lifting and getting stuck. Tried to get professional service this year and all the shops are booked until the end of August. I did recieve great advice from one service provider suggesting the tube and shaft could be rusty. Then I found this forum which led me to a link for taking the jack apart. Genious. I'm on jack#1 and found a shreaded "O" ring hanging on to the screw. Looks like it came from where the screw meets the top of the leg. Can't find details regarding the size of the "O" ring. Any suggestions?

bigfootford
Nomad II
Nomad II
After 18 years I had to replace my front jacks.. Motors still ok.

I have greased both of them both 2 times over the years.

One jack was clanking really bad... I knew that the guide at the bottom of the jack screw was broken off same as KKeller's. The other, the wafer bearing and washers were gone along with major rust on the inside tube.

I replaced both... Never have had a problem with the rears... I did tear them down about 8 years ago and did the clean and grease...They are the 4100's.

The new jacks I got are 2900lb capacity v/s2500. There is a drain hole at the bottom of the foot and the inside tube is not painted...It looks like galvanized steel. That seems like the only visible difference.

I have not seen any pictures nor info on the new HJ's shown in the previous posts... Quite interesting.

Jim
2000 2500 9.6 Bigfoot,94 F250, Vision 19.5, Bilstein shocks, air bags/pump, EU2000, PD 9260, Two Redodo 100ah Mini's, Aims 2500 Conv/Inv, 200W. solar, Morningstar Sunsaver 15A/ display panel, Delorme/laptop for travel, Wave-3 heat.

d3500ram
Explorer III
Explorer III
bump
d3500ram wrote:
I too saved the OP's first post with pictures in .doc, docx and PDF format for when I did the repair.

...if anyone wants a copy PM me with an e-mail address and I can forward a copy.
Sold the TC, previous owner of 2 NorthStar pop-ups & 2 Northstar Arrows...still have the truck:

2005 Dodge 3500 SRW, Qcab long bed, NV-6500, diesel, 4WD, Helwig, 9000XL,
Nitto 285/70/17 Terra Grapplers, Honda eu3000Is, custom overload spring perch spacers.

magic43
Explorer
Explorer
Oh My, this topic bailed me out back in August, 2012. It wasn't a lube problem but it had to be disassembled. This topic gave me the confidence that I needed to tackle the "teardown". Thanks again.
magic43