My trailer came with a hand crank jack similar to the one in the link below. Do they need to be lubed periodically? If so, where? I don't want to pry off that black cap on top unless it's supposed to come off.

http://www2.northerntool.com/product/31791.htm

 

I just installed a replacement jack on a Zieman, and as luck would have it I still had the directions lying on the garage floor...

It says in essence that you can protect it's finish with a coat of wax, and lubercation is needed if the jack ever feels rough or produces a grinding noise.

It says you take weight off the jack, remove the plastic cap on the end, remove a pin in there that holds the handle in place, remove the handle, and one of the miter gears, turn the jack upside down and shake out the other miter gear. Then there is a roll pin you have to align with a slot in a washer, so you can then tap the top of the jack screw to remove the inner tube. It says do not remove the screw from the inner tube, clean everything and work grease into the entire thread, grease up the bevel gears, and reassemble. It also says when you put it back together to make sure the roll pin is captured by the miter gear using the slot with closed ends...

Dutton-Lainson makes a bunch of trailer jacks.

Here's a page that shows an exploded view.

Exploded view typical tounge jack

 

YEs you should lube the jack every couple of years. If you dont it will eventually become harder and harder to crank, evnentually stripping out the gears inside. Some jacks contain zerk fittings and other do not.

 

we scraped an old bailer... probably 30 years old and rusting away... it was sitting in the woods for a good 20 years...

the jack on it still worked and we used it to pick it up...

i couldn't believe it wasn't seized..

that being said, we have tons of jacks on our farm, and never took them apart to greese them.... we have 2 jacks with grease zerks, and do them every few months...

 

I think for most people if they start running rough they might pop the top off and spray some lube in there, and otherwise they would wait until they stop working and just replace it...

 

My jack has a zert at the top.

 

I have the same brand jack but its the 1000lb one and it has grease fitting on it. Mine is near the handle. Ur sopouse to grease it every year.

 

I worked at a camper dealership for over 5 years and repaired/rebuilt jacks all the time. I have never had to fix one becuase it wasn't greased though. The grease in them is like wheel bearing grease, thick and gooey. It will last a long long time. The number one reason to have to fix a jack is because it was over extended one way or the other stripping the gears or shearing a pin.

 

In a real basic tool kit you only need two items: WD-40 and Duct Tape. If don't move and it's supposed to, use WD-40; if it moves and it ain't suppused to, use duct tape.

Seriously, I pour a little gear oil (used gear oil mind you) on the top of my worm gears of the jacks that do not have fittings. I let is drip and work it's way down there while I spijn the handle one way and then the other. I figure it's like chicken soup - nobody ever died from it!