Trailer jacks are an often ignored piece of equipment on your boat trailer. But if you ever have trouble with yours then you quicker recognize how important it is.
This simple maintenance addresses the most common problem I’ve encountered with jacks, and can keep the problem from happening in the first place.
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The inside of a trailer jack is pretty simple. The shaft contains a really long screw. This screw has a “nut” threaded on it that is attached to the cylinder that moves up and down.
The sticking out of the side connects to the right angle gears, which in turn connect to that big screw.
Turn that handle and the big screw turns, which raises and lowers that nut, which in turn raises and lowers the trailer.
Like any moving metal piece it needs lubrication to do its job correctly. This is especially true for the jack which will get exposed to road grime and occasionally get submerged in water, both fresh and salt.
Grease not only helps the parts move smoothly, but provide some protection from these elements and rush.
You should performance this maintenance when:
- The jack starts to stick or becomes hard to crank
- A couple times a year (more often if the jack is regularly exposed to saltwater)
Start by getting a can of white lithium grease, like this one:
Next take the cap off the top of the jack. You can do this by undoing the screw right below the cap. The cap should then easily come off. You can see the screw here between the handle and the cap.
Be aware that some models of jacks have a zerk fitting. If you have one of those, then instead of taking off the cap use a grease gun to apply new grease through the zerk. I’ve thought about installing a zerk fitting on mine, but frankly taking the cap off a couple times a year is much easier than installing the fitting.
Once the cap is off, squirt in a generous amount of the grease. Make sure to cover all exposed gears.
Next replace the cap and screw.
With the trailer attached to your car, fold up the jack so it isn’t holding any weight. Squirt more grease up the moving cylinders – both between the 2 cylinders and the inside where the screw is.
After the grease is applied, use the handle of the jack to extend the jack to the fully expanded position and then back to fully collapsed. Apply more grease in each of those positions.
Work the handle a bit more, and then you are done.
That grease will help keep the jack moving smoothly and keep it easy to crank up and down.
2 thoughts on “Trailer Jack Maintenance”
I bought an old sylvan boat and trailer. The cap and screw on the Jack was missing when I brought it. Where can get a cap and screw so I don’t have to buy a new Jack?
Amazon carries them https://amzn.to/3dvb3LB. Also check etrailer.com
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