14,000 lb equipment trailer jack issue

[michford]

Having an issue with the drop foot jack on my equipment trailer. With no load on the jack, the jack runs up and down. As soon as there is a load on it, the jack will not lift. I opened the small square top cover, and the bevel gears are engaged on the 90 degree shafts between the handle and the vertical jack. Anyone ever ran into this, and if so what is the fix? Or is it just as much to fix as replace the whole jack? Equipment trailer is a Big Tex 14K.

 

[Jim.ME]

Having an issue with the drop foot jack on my equipment trailer. With no load on the jack, the jack runs up and down. As soon as there is a load on it, the jack will not lift. I opened the small square top cover, and the bevel gears are engaged on the 90 degree shafts between the handle and the vertical jack. Anyone ever ran into this, and if so what is the fix? Or is it just as much to fix as replace the whole jack? Equipment trailer is a Big Tex 14K.

Will not lift as in the handle turns, but the leg doesn't move? Or it won't because you can't turn the handle once the leg foot makes solid contact with the ground?

 

[michford]

Can continue to turn the handle, jack just won't lift once it has a load on it. Without a load, the handle will run the jack up and down.

 

[Jim.ME]

Can continue to turn the handle, jack just won't lift once it has a load on it. Without a load, the handle will run the jack up and down.

Many pin the gears to the shafts. Could be a pin that holds a gear to a shaft has sheared. It may catch and drag enough to move the leg when there is no load on the leg.

 

[J Hamilton]

Many pin the gears to the shafts. Could be a pin that holds a gear to a shaft has sheared. It may catch and drag enough to move the leg when there is no load on the leg.

My thoughts as well, a pin or keyway sheared.

 

[caterpillar guy]

pin or key sheared and they need greased often like a few times per year. I greased mine each time I greased the truck and trailer so about every weekend. Or 2500-3000miles. IT hardly ever was unhooked from the truck also.

 

[BarnyardEngineering]

Can continue to turn the handle, jack just won't lift once it has a load on it. Without a load, the handle will run the jack up and down.

Should be able to see down in and determine that the jack screw is turning inside the bevel gear. If the gear is spinning on the shaft you sheared that pin. If the shaft spins with the gear, you stripped out the jack nut.

Does the jack hold weight, or does it collapse? That's another indication. If it holds weight, pin. If it collapses, nut.

 

[michford]

Should be able to see down in and determine that the jack screw is turning inside the bevel gear. If the gear is spinning on the shaft you sheared that pin. If the shaft spins with the gear, you stripped out the jack nut.

Does the jack hold weight, or does it collapse? That's another indication. If it holds weight, pin. If it collapses, nut.

View attachment 61427

Great cross section. Watched a good youtube video, I'm betting the crosspin in the bottom of the bevel gear on the screw & nut assembly is the cuplrit as the jack holds weight.

rebuilding square tube jack

 

[michford]

Removed jack from trailer and disassembled. The screw and nut appear to be the problem. The nut will slide up and down the threads of the shaft. I have a replacement shaft and nut assembly on order from etrailer.com will update next week when replacement gets installed into jack.

 

[caterpillar guy]

Probably would have been cheaper to go to junkyard and get one off from and old semi trailer and would probably out last your trailer. I've got some on a trailer that was built in 1998 still work with no issue never been apart. Sounds like your jack is not built heavy enough for the job.

 

[michford]

Probably would have been cheaper to go to junkyard and get one off from and old semi trailer and would probably out last your trailer. I've got some on a trailer that was built in 1998 still work with no issue never been apart. Sounds like your jack is not built heavy enough for the job.

I don't doubt for a second that a square tube trailer jack built in the 90's or earlier will outlast anything built today, but I wouldn't even know where to begin searching for one off an old semi trailer. Even if I found one, I'd probably have to modify it to mount it to my trailer. Sounds like the jacks built today don't like to be run to the ends of their threads so I will keep that in mind when using after repairing. The parts from Etrailer set me back $105 with shipping so the cheap parts have a cheap price. If I have problems again, maybe I'll try to search out an old semi trailer jack and see if the internals would fit inside my jack. Thanks for the idea either way about a semi trailer jack caterpillar guy!

 

[michford]

Parts came in a day early from etrailer so I got busy and put it all back together. Works great, hope I get more than 7 years out of this screw assembly.

 

[Jim.ME]

Parts came in a day early from etrailer so I got busy and put it all back together. Works great, hope I get more than 7 years out of this screw assembly.

Thanks for letting us know, that closes the loop for anyone reading this in the future.

 

[BarnyardEngineering]

Parts came in a day early from etrailer so I got busy and put it all back together. Works great, hope I get more than 7 years out of this screw assembly.View attachment 62615View attachment 62616View attachment 62617

I've got two trailers with jacks like that, both beat and busted and way more than 7 years old. They won't give up. I'm looking for an excuse to replace them and they just keep working...