Happijac new vs old?
I have electric Happijacs, possibly 4600 (numbers are illegible) that are complaining. I could: 1) remove, clean and relube 2) replace the legs with 4220 or 4820 legs 3) replace the whole set...
Forum Discussion
Things changed when Lippert bought Happijac. Not that they were perfect before.
I think my jacks are the ball screw version, maybe the back ones are Acme screw. The problem with the ball screw is it works really great when perfectly clean, but suffers badly from dirt or rust and is very difficult to clean up again as dirt and rust gets inside the ball nut. The writeup you reference appears to be an Acme screw jack. One motivation to buy the new jack legs is they are all Acme screw now - takes more torque to turn but much more tolerant of dirt and rust.
The incompatiblity of the motors seems to center around the lack of an overload clutch in the new ones, and its replacement by an electronic current sensing overload. If you just listen to the jack and lift your finger at the end of travel neither of these is necessary. Mine are obviously laboring (dirty or rusty or lack of lube) and the overload clutch is occasionally slipping. The incompatibility of the electronic control seems to be that the newer ones can supply 25A while the older ones only 10 or 15A. This seems to be the solution to the switch from ball screw to Acme screw on the new 4800 (which replaced the 4600), requiring more torque. But again, if I am running them well below capacity it may not be needed - if it requires 25A at 2800 lbs full load, it may require only 10A at 1000 lbs. If I buy the jack legs and discover I need the control unit and motors, bought separately it will cost about $300 more than the set together. The Reico-Titan offering is a little more, and would require modifying the mounts.
I'm not planning any trips for a month or so, I'll probably remove one or two that are the worst and have a look inside.
I think my jacks are the ball screw version, maybe the back ones are Acme screw. The problem with the ball screw is it works really great when perfectly clean, but suffers badly from dirt or rust and is very difficult to clean up again as dirt and rust gets inside the ball nut. The writeup you reference appears to be an Acme screw jack. One motivation to buy the new jack legs is they are all Acme screw now - takes more torque to turn but much more tolerant of dirt and rust.
The incompatiblity of the motors seems to center around the lack of an overload clutch in the new ones, and its replacement by an electronic current sensing overload. If you just listen to the jack and lift your finger at the end of travel neither of these is necessary. Mine are obviously laboring (dirty or rusty or lack of lube) and the overload clutch is occasionally slipping. The incompatibility of the electronic control seems to be that the newer ones can supply 25A while the older ones only 10 or 15A. This seems to be the solution to the switch from ball screw to Acme screw on the new 4800 (which replaced the 4600), requiring more torque. But again, if I am running them well below capacity it may not be needed - if it requires 25A at 2800 lbs full load, it may require only 10A at 1000 lbs. If I buy the jack legs and discover I need the control unit and motors, bought separately it will cost about $300 more than the set together. The Reico-Titan offering is a little more, and would require modifying the mounts.
I'm not planning any trips for a month or so, I'll probably remove one or two that are the worst and have a look inside.
