Happijac new vs old?

[HMS_Beagle]

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 setup with 4820 legs and new controller

Happijac/Lippert do not publish much detail on these jacks, for example why the 4220 is rated lower than the 4820: tube strength? acme screw pitch? something else?

Obivously the cheapest is #1, provided they can be cleaned up. I think they may be the ball screw version (at least on the front) which are often too far gone to fix. Also the tubes on the old style jacks are somewhat - flexible - and so going to the new jacks has some appeal.

What I don't know is, will the old motors and controller drive 4820 legs? they have upgraded both and used to say (can't find it anymore) that the 4820 required too much current for the old controller. I'm not near their capacity (pretty evenly distributed at <1000 lbs each) so they might work fine.

Does anyone have an informed opinion about the old vs new legs, old vs new (vertical) motors, old vs new control? Anybody done this upgrade? New legs are about $1750 for the set, whole setup is $2750 with new motors and controller.

[HMS_Beagle]

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.

[Joe417]

I don't think I have any info that will help you, just the same info you've already acquired.

From what I've gathered, the new vertical motor is not compatible with the old controller. You will need to replace the controller also if you use the new motors.

I'm not sure if the 4820 is compatible with the old motors. I had a Texas dealer tell me they were not. The 4800 was compatible with the old motor but Lippert/Happijac seems to have discontinued them.

I tried to contact Happijac quite a few times last summer to get some straight information about the 4800s but got no response from them. I assume based on their silent business practices, happijac intends to force one to buy a complete jack system.

I have 4500s which I believe are rated the same as the 4600s you have. They lift my TC but I don't think they are strong enough to handle it. They make me nervous.

Back in June, I started to replace my 4500s (jacks only) with the 4820s but, since I couldn't determine what happijac component may be compatible with what and I didn't want to spend what a complete 4820 system cost, I ended up straightening and rebuilding my 4500 jack myself (for the time being).

I also found that the Reico Titan system handles about the same weight as the 4820 and was selling at that time for a bit less.

If all your jacks need is re-greasing, there is a good video out there at

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/22881036.cfm

. I've seen a few posts that say happijac will refurbish them for you.

[ajriding]

number 1 first. it will be free except your time, and that is free also. They need re-lubing all the time, the grease instantly is pushed out of the gears when you use it.

Flexible legs? Have they done the job so far? All the legs are doing is lifting from the truck and lowering down on to a support stand. are you storing it on the legs only? Keep the legs if that is the next cheapest thing.

[JimK-NY]

A couple of years ago, I needed to order a replacement for one of my old jacks that had frozen with broken parts. A tech rep at Tweety's had all the information on recommended replacements and compatibility of parts. I suggest you give a call and see if they can help.