Harbor Freight Bolt Together Kit Trailers

Shorty Misc Projects >> Article By Shorty


This is the basic Harbor Freight Haul-Master Boat Trailer. It used to be rated for 600 lbs, then later they upgraded the rating to 800 lbs. The springs look like the same ones on their mini trailer, which is rated for 1100 lbs so I figure that is realistically the max if you wanted to push it.

I have a number of small boats, but the one that sits on the trailer the most is my PDRacer.

Took me a while, but I finally figured out a simple and sturdy way to make a bow stop for the PD, since it has a transom bow. The stop is just a few pieces of angle iron bolted together like shown in this picture. It is very easy to remove for when I want to carry a different & longer boat.


The winch post that comes with the kit is adequate for typical jon and small power boats, but I mostly carry small sailboats. After a number of experiments, I settled on this arrangement for the winch post. I welded a piece of fence post to the existing winch post and use that for a mast support. A couple of pieces of angle iron make a diagonal support to hold the post upright -- those pieces are painted black.

A great addition to the trailer is a simple plywood box for hauling stuff. It fits between the fenders so all I have to do is remove the aft bunk board and drop the box on.

The trailer is rated for 600 lbs, but the springs look identical to the ones used on the HF trailer which is rated for 1100 lbs. I do a lot of projects in my yard that needs bags of concrete, and often haul 800 lbs of concrete per load. I have also carried up to 1200 lbs, but find it hard to push that weight thru my yard by hand, so backed down to 800 lbs.

I have put many, many highway miles on my HF trailer and am very impressed with it's performance for such a cheap and simple bolt together kit that it is.

Easy Assembly Steps
The best way I have found to assemble Harbor Freight trailers is to build them upside down, with all the parts propped up on 2x4's. This gets all of the parts off the ground so you can put a box wrench on the bolt head (which is now between the floor and the trailer frame), and use a socket wrench on the nyloc nuts, which is now facing the sky. As for whether to put the nut facing upward or down -- I consulted an aircraft enthusiast friend of mine, he said the rule of thumb is to always put the nuts on the bottom, so that if they fall off, you still hopefully have the bolt in the hole, holding stuff together.



Haul Master Heavy Duty Mini Trailer Kit



This is the mini trailer kit, it is dirt cheap at between $170 and $200 depending on if you catch it on sale. The tongue that comes with it is ridiculously small, so I purchased a long piece of square tube steel as a replacement tongue. Since everything was bolt on, it was easy for me to make this change. I made a very simple set of bunk boards that bolted on top of the frame bed, and tried using it without a winch post. I made a winch post from some 2x4 and plywood. The only thing I didn't like about the trailer was one day when I was backing it down the boat ramp empty, it caught on a piling to the side of the ramp and the whole frame twisted sideways. Wasn't really a problem to fix, I just kicked it a few times and it was pretty much back to normal.

Here is a diagram of an easy to make wooden winch post and mast crutch.

I see lots of the mini trailers around carrying boats. I think the attraction is the initial cheap price, and if you can weld & have lots of scrap steel laying around, you can quickly fabricate a very nice, usable boat trailer. Possibly another big feature is that the trailer kits come with a manufacturer's statement of origin (MSO) so that when it is time to register the trailer, it is a lot simpler than a 100% home made trailer.

As you can see in this picture, you can make a very elaborate trailer for your boat.

This is a bit ambitious, looks a bit on the top heavy side to me, but it shows a more extreme version of what you can do.

Other HF Trailer Kits



If you like the mini trailer, HF carries a couple of other versions similar to it. This is their extra heavy duty model that comes with a metal bed, bigger tires, and heavier springs to carry a larger load.

Occasionally, they have a galvanized PWC trailer - the advantage is that it is galvanized, so if you dip your trailer in salt water often, the trailer frame won't take as much abuse. I ordered one, and it literally took 6 months to arrive! When it finally did, I put it together with a deck & several cross beams below the deck for support, and replaced the tongue.

Also I installed a set of fence post stakes along the perimeter and made the surrounding gate so that I could carry gravel, dirt and other messy stuff. That was a lot of work, and on a later trailer I just made a plywood box that sits on top of the trailer - see the top of this page. The simple box works better.

I used to be a boat dealer, and would acquire boats on trailers that did not have working lights. I made a "light bar" from a 2x4, so I could strap it across any old boat and presto, have working lights. Some of the features which made it more handy was 2 of the "pull thru jaw" cargo straps so I could quickly tighten it down. I also added a place to wind the wires on top of the 2x4, so when not using the wires were wound up and tidy.