Quote: The only reason to pull apart the jack is to lube so if it can be done with a small hole and arsol spray lube, why not?
Serpa:
Absolutely excellent idea!
Where (precisely) would you say a small hole in the side of the jacks would be required to lube the difficult to get at gear? Say, measuring down the jack from the *removed* top plastic cap.
Ok, here is the problem area. If you go to
http://www.happijac.com/jax/jprodov.php
and look at the see thru picture of the jack you will see what I’m talking about.
First, on the regular color image of the jacks internals, not the 3D drawing, you can see the tip of the jack screw, ball or ACME. One fo the parts you are interested in is the very top brown piece that mounts on top of the screw shaft. It looks like you have a couple set screws in it if you look close. This is the rotating metal part of the jack. It looks like a piece of 1.5 inch bar stock that has the top 3/4 of it turned down to about 1/2 inch. This whole thing is one piece and is about 6 inches long. It is attaced to the worm gear by set screw or pins. The fat part will be called “fat” and the skinny shaft, about ½ inch in diameter will be called the “skinny” part. On top of this brown colored (its metal) pin assembly rides the brake assembly which is a tightly wound square wire spring. The spring is not under any tension as you can uncoil it with your fingers to remove it. It would be difficult to even pinch yourself with it. You can see the spring in the 3d drawing. It’s the shaded round portion of the spring under the stacked squares that the horizontal crown gear is on top of. If you closely look at the 3D image, it will look like the round shaft has the spring wound around the “fat” part of the rotating shaft and the large diameter area of the shaft exits out the other end of the spring. You will have to zoom in on this. Actually there are two pieces there. The brake spring holds them together. The brake spring is half wound around the large diameter fat area of the rotation pin and the other end of the spring is wrapped around a large (1 inch tall) round chunk of metal with a hole through it. It looks like piece of 1.5 inch bar stock with a hole drilled through it. The hole allows the narrow diameter skinny end of the shaft to pass through the center of the spring, center of the bar stock piece, through the square plates (2), and through the horizontal crow gear. Now look at the cut a way picture/see through black and white image again. This will be hard to ID the thrust washer. First, at the top you will see the large 1.5 inch horizontal crow gear. The vertical crown gear encircles the manual crank hole. This is where the oil goes when you put it in through the hole where the crank goes. You’ll see the problem with this in a second. The horizontal crow gear rides on a square piece of metal. If you look close, there are actually two square pieces of square metal. The larger one, the one on top, is welded in the tube making a top and bottom chamber. The top chamber is where the crow gears are and where you put the oil. The oil does not get to the bottom chamber unless it dribbles down the side of the tube and thus doesn’t get on any springs, gears, etc. in the bottom chamber. It may do some good by getting a very small amount on the horizontal and vertical gear, but these are “greased” from the factory, not oiled. IMHO, it’s very useless to oil. Here is the problem the bar stock piece is half encircled by the brake spring and the other half just protrudes out. This gives the 3D picture the appearance that the fat end of the rotating pin assembly actually exits the spring. Not true, it’s the bar stock piece that exits the spring. There is actually about a 1 inch air space inside the spring’s coils. Remember, the rotating pin assembly rotates with the long 4 foot worm gear which rotates the brake spring, which rotates the bar stock cylinder shape piece with the hole in it. The other half of the bar stock piece of metal that exits the spring is what rides against the bottom (smaller) square metal plate. The bottom square plate is the thrust washer and will fall out freely upon disassembly. It is not attached in any way. It just rides ontop of the round bar stock peice which is entrapped by the spring. It is kept from turning by the fact its square and so is the tube it’s in. The smaller square under the larger one will be called the thrust washer. It has about 6 small divots in it. This is where I thought ball bearings were to go. However, the divots hold grease not balls. This grease provides the lubricant from the 1,500 lbs of weight from the camper. The rotating bar stock piece spins against the thrust washer. Both surfaces are flat. As you can see, there is not way for lube to get there. The thrust washer is about a ¼ inch thick. So, if you find the weld on the outside of the jack, looks like a slight deformation of the side, you could drill a hole about ¼ inch under it to spray white lithium grease between the two rubbing surfaces. To help the grease get in there, you should remove all weight from the leg and press down on the foot to help separate the two surfaces and spray away. What ever drips down from the thrust bearing will lube the worm gear from the top. Any lube above the large blocks that ride the worm gear will run down between the two square legs of the jack. Clean this up by extending the jack and wiping down. You don’t want it to attract dirt. Use car wax like Happijac says. To lube under the blocks, you will need to drill a second hole far enough under the blocks as to squirt the worm gear. The large blocks under the rotating pin assembly are what drives the inner tube/leg up and down the worm gear. The worm gear resides inside the inner leg (black part). So, if you want to lube this, you will need to make the hold go through both inner and outer leg. Note that if you fully extend the leg to lube the thrust bearing, all the worm gear will be above the plastic block and by moving the jack up and down will distribute the lube and drilling the lower hole will not be necessary. The worm gear also needs grease as mine were getting dry.
Remember, as you drill, you will be making metal shavings! What I did was to often coat the drill bit with axel grease to make the shavings stick. Then, very often, wipe the drill bit and shavings off, recoat with grease and drill a very small amount again.
All of this is at your own risk. As you read, there is a brake spring in there.
PS. Just drilling the hole in my jacks to lube did help a little but didn't totally cure the problem. It did not help at all on my friends jacks (identical). His noises were much more seveir and lubing did nothing. His camper would barely come down. My thrust washers were decently gouged, too late for lube to help probably. We never looked at his. After the mirror like polishing of my thrust washers, the jacks have yet to make any noise after about 8 uses. My friends were so bad that the clattering clutch was activating most the time he tried to lower the camper. He ended up buying a new one before I found out how simple it was to take apart. I'm not sure I'd have drilled the holes since pulling them apart was simpe, but now I will keep them lubed yearly since the holes are there. Probably a good idea this thing called preventative maintence. Make sure you cover up the holes after drilling to prevent dirt entering.
Beddows wrote: Don't do it. I know I am not supposed to mention names on this forum, but this is important. I received a phone call from Happijac about 6 months ago regarding a thread here about rebuilding Happijacs. They are extremely concerned about anyone doing this, especially trying to make "improvements" to them. They are concerned that someone might end up injuring themselves or destroying their camper. they are not as simple as they look and in the prior previous posts the "improvements" suggested would, according to them, make the jacks unsafe. I would suggest you phone them first before attempting to rebuild the jacks or service them other than lubrication. Risking $30,000 worth of camper to save a few bucks on having them professionally reconditioned is not good economics.
They specifically told me that the fatfox modification was dangerous.
OK, please share who will do this? How much does it cost? What is the warranty?
'00 ArticFox 1150, torklift
'02 F350 CC 4x4 V10 auto 3:73-LS, Firestone ride-rites, RMX monotubes, Toyo M608z 245/70R19.5
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