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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

northsantiam
Explorer
Explorer
Good thread and found to be very helpful. I had 2-4100 jacks that had bad thrust bearings, 1 completely destroyed and 1 on its way. I was able to find these little thrust bearings at MSC Industrial supply. I serviced the front 4600 jacks, they looked good but a little short on grease at thrust bearing and thrust plate. Had to adjust clutch on one of them a tad. Cannot figure out how to attach pictures so if anyone wants to see what I had and what I bought, drop me an email.

Grit_dog
Navigator
Navigator
Bringing this back to the top. Found it very useful this weekend.
Thought I had a jack with stripped teeth or threads or something. Turned out was a bunch of rust accumulated jamming it up. Thorough disassembly greasing and oiling made it work like new again.
Probably should do the other 3......
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5โ€ turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Travels_with_Yo
Explorer
Explorer
What a read ! Finished all 17 pages in one sitting. I am new to TCs and trying to absorb as much as I can. We have a new 2016 camper and I noticed something in the Happijac manual that came with the camper that relates to many posts here about the different rates at which the legs extend and retract. The manual was very clear in stating that the four corners of what has been called the "box" do not carry equal weights. Some corners are heavier than other corners and that alone is the reason the legs move at different rates (speed). I just thought I'd add this to the pile of knowledge here.

bigfootford
Nomad II
Nomad II
trail-explorer wrote:
Reminds me of the jackscrew on the MD80.



Oh yea, some of us can relate! Same technology for wing flaps too!

US Navy P3's.

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.

trail-explorer
Explorer
Explorer
Reminds me of the jackscrew on the MD80.

Bob

Moose10
Explorer
Explorer
What a great thread!
I recently had to service one of my rear jacks, but not the screw, the actual 12v motor. So the camper had been on the truck for about six months, and we were out camping and I went to lower the two rear jacks for stability. One worked and the other didn't. The first thing I did was check the fuses and of course the rear passenger side was blown, so I replaced it, tried the jack again and blew another fuse. To make for a shorter story, after getting home from that trip I pulled the jack off the camper and removed the motor to find out that the coil wires were bound up by rust on/in the magnet or stator. Also, the white plastic cup around the motor had water in the bottom of it.
I took it all apart, cleaned and dried everything, put it back together and silicone all the seals and it works fine now. I'll probably inspect and seal the other three now too.
2001.5 Ram 3500 4x4 QC Sport ETH/DEE
on Vision Hauler 19.5's
'06 Arctic Fox 1150
'09 Nissan Murano S
'14 Ford F-150 FX4
'03 Polaris 700RMK VE, MBRP can
'04 Polaris 600RMK VE
'04 & '05 Suzuki Eiger 400's

bigfootford
Nomad II
Nomad II
magic43 wrote:
Wow, it is good to see this thread again. I believe that it once was a "sticky".



Still is a sticky...

Truck camper university, scroll down to jacks

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/25966285.cfm

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.

carrnutt
Explorer
Explorer
Definitely a life saver. Well money saver, anyways. After performing this maintenance, my jacks all work great. I still have one that's going to need to be replaced, but working for now, as opposed to replacing all four. Thanks again!!!
2014 Cougar 31SQB
1993 Dodge D350 Cummins

magic43
Explorer
Explorer
Wow, it is good to see this thread again. I believe that it once was a "sticky".

Since I disassembled, removed the skimmed paint, and properly lubricated my jacks (in August, 2012) I have had absolutely no problems. This thread was a lifesaver.
magic43

sleepy
Explorer
Explorer
This is very good post... thanks for taking the time to capture the repait with detailed pictures.

I mighty be able to help with one of the simplier problems... rust!

Ijanet and I have spent a lot of time on The Gulf of Mexico Beaches over the last few year.

My jacks (Atwood) have a fine red rust hear and there all over them...

I was in my local Home Depot to get some stain for a home project... Ed, the paint department expert asked if there'd be anything elso.

I told him about the rust... asked if he had any ideas.

He suggested CLR, CLR

a product called Calcium, Lime, Rust


It was less than $6.00... I thought what the heck... I'll try it.

When I got home I used a scotch brite pad and the CLR on my jacks... hoping to get enough of the rust off to paint them...

Within a few minutes they were as clean and brilliant white as they were when I bought the camper new.

I will still paint the jacks with a thick, RustOleum paint... using a very small roller (that costs about $3.00 and comes with a roller pan.

Thanks again

Sleepy
2003 Lance 1161,/slideout/AGM batteries/255W Solar/propane generator/Sat dish/2 Fantastic Fans/AC/winter pkg
AirFoil, Trimetric, LED lights, Platcat vent heat

2003GMC K3500 LT/Crewcab/duramax diesel/allison/dually/4x4/OnStar/front reciever mounted spare

mjkruid
Explorer
Explorer
I found this topic while searching for happijac maintenance. This is the best information I've found anywhere. Thank you for posting this!
I have happijac 4500's, 14 years old. I purchased this camper this spring and the jacks are in dire need of service. I have 2 completed and they work great. My problem with the remaining 2 is that I am unable to pull out the manual socket. I have removed the C clip and the sprocket is loose on the inside but the socket will not come out. I have tried everything I can think of short of welding in a coupler nut and using a slide hammer. The drawback to this is the socket will be ruined.
Any thoughts would sure be appreciated.

bigblue1978
Explorer
Explorer
Thanks, Bigfootford. I didn't know the proper terminology. The swivel to which I refer is perhaps called a centering block. It is internal to the black tube and is attached to the bottom of the acme screw. one of the members used a band saw to cut the black tube apart and the picture of this part shows excessive rust. I only intended to explain how I delivered hypoid oil to this part. My jack was binding, but from what I could see everything appeared to be well lubed. I did what I could to lube that which I could not see and now the problem is solved. I will try to be more accurate in the future and also to have pictures and illustrations as well.

bigfootford
Nomad II
Nomad II
bigblue1978 wrote:
Great post. If the swivel at the bottom of the acme thread is badly rusted, the black tube will torque twist. This will cause the paint scraping because of corner to corner rubbing. This will also cause lots of groaning and grinding and popping noises. I lubricated my 4150 with 90 weight hypoid oil. with the black tube secured in the vertical position, I extended the screw as far as possible and then poured the oil(a few drops) onto the nylon nut and let it drain down. This takes several hours. I repeated this several times. Working the acme thread rod up and down, it eventually was loose enough to turn with only my thumb and forefinger. After everything is loose, grease the whole rod.
The nylon nut can fail and become stripped. The steel safety nut should prevent catastrophic failure. Similar nylon nuts are used in adjustable hospital beds and they do fail. The nylon nut can be replaced, but you will need advanced machining skills. For all that is at stake, replace the whole jack instead. A new jack is cheap insurance.(Oil the new jack with the hypoid oil.)


Welcome to rv.net Bigblue1978, I'm impressed that you know all about these pesky jacks having only joined RV.net TODAY....

Been through exactly what you described except that I had the jack on the bench and apart. I used WD-40 to loosen the acme nut, running it up and down on the threaded shaft with a drill attached to the TOP end... Took a while but finally the nut moved freely. Greased it with boat axle grease.

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.

bigblue1978
Explorer
Explorer
Great post. If the swivel at the bottom of the acme thread is badly rusted, the black tube will torque twist. This will cause the paint scraping because of corner to corner rubbing. This will also cause lots of groaning and grinding and popping noises. I lubricated my 4150 with 90 weight hypoid oil. with the black tube secured in the vertical position, I extended the screw as far as possible and then poured the oil(a few drops) onto the nylon nut and let it drain down. This takes several hours. I repeated this several times. Working the acme thread rod up and down, it eventually was loose enough to turn with only my thumb and forefinger. After everything is loose, grease the whole rod.
The nylon nut can fail and become stripped. The steel safety nut should prevent catastrophic failure. Similar nylon nuts are used in adjustable hospital beds and they do fail. The nylon nut can be replaced, but you will need advanced machining skills. For all that is at stake, replace the whole jack instead. A new jack is cheap insurance.(Oil the new jack with the hypoid oil.)

devildog1971
Explorer
Explorer
It can be a messy job
2019 Northern Lite 10-2 EXCDSE Dry Bath 2007 G M C dually crew cab and 2018 Harley Davidson Limited Low