Happi Jack over extended

Next time you have your jacks apart you might consider extending the orange travel limit indicator all the way around the jack leg. I used day glow orange paint.

Originally they are visible only when standing in front of them, and not from the back of the truck where I raise and lower them using the keypad.

You have to watch your leg travel real close when you are raising it, as it turns out the be a real big headache. I got caught by doing all 4 jacks at the same time but did not realize one jac was in a depression and it was the one that over extended. The motor made a real loud clacking sound and that was it the leg was fully up and would not go down.
I played around with the other 3 till I got the pressure off the jammed leg. Then I was able to remove the leg from the TC and lucky I had copied KKELLER14K's writeup. I never took one apart before but that writeup was my savior but did not know for sure. When I tore it all down to the wormgear this is when I found the problem.
The motor had tighten the gear locking the two together like a lock nut.I knew from that post not to put presure on the top spindle as it may break at the hole where the pin came out. I had learned not to use vise grips on threads as they do not lock real tight and would probably slip and do more damage to gear. I used a pipe wrench that locked on gear and was able to break the lock nut effect on the worm gear. I then uses a fine fine to fix up the wrench mark on threads and cleaned it up so the were no filings. Then I lubed the gear as I had it all apart anyway and reassemble it. All worked great and saved me alot of money to get someone to do this and they probably would have told me I need a new leg.
This is a great site and many helpful people. You can get in alot of troble fast and it is nice to know help is not far off.
Again thanks to all.

I have added this thread to my favs and will print out the directions/pics and add them them to our camper book of knowledge. Very helpful.

Your welcome...glad to see that this thread still gets used. I was in the dark at one time also and decided it was time to do something about it. Now that the info is there, people just like you can do it yourself. It's not all that hard and with some mechanical skill, save some money you can use in other places. So glad to hear that it worked out.... One quick note to any others who have these jacks: It is a good idea that you don't tighten them in either direction until you hear the clutch clicking. This usually happens when putting the jacks in the full up position. You can hear the motor start to labor just before this happens...just run it back down a tiny bit. If you have it on the truck for an extended period of time, it can also get stuck in the up postion if the jack is too tight. Each leg has a do not extend beyond this point printed on the leg at nearly full extension, you can see it in the pics. It is a good reference to stop right there before over extending the leg. When you put the leg back in the outer tube, make sure you have it pointing outward so you can see it. I would say this is an obvious thing but we sometimes forget it is there.

Thanks for the excellent write up on breaking down the happijac leg. I got it down to the worm gear and it was fully extended and would not screw back in. I tried turning the gear at the top with a socket but was afraid I would snap the top where the pin goes through.
I finally decided with nothing to loose to use a pipe wrench at the very top of the gear and see if that would break the tight seal on gear nut. This worked and now the worm gear is free, so I touched up the wrench marks with a fine file and regreased it all and reassembled it.
Thanks for the writeup and all help.

Well , I have the whole jack torn apart as per doing a lube job and the intructions sure helped on this part.
What I have now is the worm gear sticking out about 3feet and it will not turn back into the lower tube. I do not want to over force this gear incase I break the top part where the pin goes through.
Looks like I need to get the gear out of the lower tube to restart the worm gear in the threaded part.

UFO , you mentioned roll pin ---easy fix , can you elaborate, thanks

I would say you broke a roll pin easy fix.