Happijac Maintenance
Step One
Check all mounting screws and other hardware frequently for tightness and proper jack alignment .
While checking the mounting hardware is secure is easy, not so checking the alignment of the jacks. This is best done with the camper mounted on the truck on level ground. Extend the jacks till they nearly reach the ground. Measure the distance between the top of the jack and the jack opposite and then the bottom of the jacks. It should be the same, or very close. You may need to alter the bracket or fit a washer or two to the bolts where the jack is mounted. Remember a small adjustment at the top will make a large adjustment at the bottom.
If you have a motor making noise while lifting and the camper is level then there is every chance you have a misaligned leg or jack. This could blow the fuse in the control board or worse kill the motor.
Step Two
Clean mounting brackets and both inner and outer tubes of jack and wax the tubes with Carnauba wax every 6 months. You can only wax the outside of each steel tube. Cleaning the inside of the outer tube is near impossible.
It is important to check for any corrosion on the inner tube. If it is evident, it must be removed. I have done this with fine grade wet and dry paper, being careful not remove any more of the galvanising than is already corroded and not to remove the height indicators from the jack. Once smooth it should be waxed and checked regularly.
Corrosion if left unattended can cause the legs to seize and then the motors will fail, which is costly.
Never apply grease or oil to the tubes. It collects dust and jams the operation of the legs and is bad in the long term.
Step Three
Fully extend jacks to red safety line once each year. This redistributes lubrication evenly on the screw shaft. Remove top cap and re-grease gears (if needed) with white lithium grease. Lightly oil bearings
This sounds simple enough but not always so. There are only two screws to be removed to take the motor off but you must be careful not lose any of the springs, washers or other parts that will surely jump out when you are not looking. They must be replaced in the correct order. Adding some lithium grease to the gears etc is easy. If you have to add machine oil to the screw shaft underneath is harder is there is no oil hole in the crank.
Again, only use lithium grease and machine oil (not WD40 which is a good multi purpose cleaner and lubricator but not a good long term lubricant).
Step Four
After periods of non-use, or anytime the jack seems to labor more than usual, place a few drops of light machine oil into the oil hole in the crank socket, then run the jack to distribute the oil.
Most of the newer jacks have a hole inside where the manual crank is inserted. You will find it on one of the flat hexagonal surfaces inside. Rotate the crank until the hole is facing down so the oil will run out. Older models do not always have this hole so you have to get the oil in by removing the cap (manual wind jacks) or the motor for auto wind jacks.