Harbor Freight Small 40.5×48″ Trailer


I wanted a small utility trailer to haul around general house / yard stuff as well as something that would work for camping in the mountains of Colorado in style. I’m taking up flyfishing and it just sounds like a nice change of pace to go fishing / camping on the weekends and try to get away from all the crazyness / monotony of the work world and unwind in a way that did not bust my ass in the process, i.e. climbing, biking etc… At any rate, I needed a small trailer that would work behind a Honda Accord (yes I own just about the most boring car there is, but the damn accord is hard to kill, more mods on the Honda will likely follow in the future). Standard sized trailers are great for hauling full sheets of plywood but an 11′ long trailer is a bit ridiculous for a car with a max towing capacity of 1000lbs. I found some pretty cool trailers at SpaceTrailers.com, but by the time you tricked it out it would cost ~$3K, which is ridiculous. So I went where any cheap-o would go, Harbor Freight. And yes, this trailer is true Harbor Freight material. For those who aren’t familiar, Harbor Freight is basically the Ikea in the world of tools. Yes, such a place exists, and they have franchises all over the world peddling dodgy shit as tools. Some things work as advertised, but generally it is a bit more of an engineering challenge, and mechano-electrical endeavor than even simply assembling Ikea furniture. In point of fact, this trailer needed to be welded rather than bolted together. Built square (obvious, but not detailed at all in instruction “manual”). Re-engineering of the trailer receiver. Design and fabrication of the trailer “cage”. And a little multimeter work to debug the ground fault in the wiring. Plus some soldering or crimp connector equipment. So all-in-all if you feel intimidated by assembling furniture, give up now. Ok, onto the build. I don’t have nearly as many pictures as I should to describe the process I will try to recall what I did from memory. Your results may vary. Also, my initial design was taken from Charles Trailer Build , his site may clear up some of the things I may have missed in this post.
    • First: Unloaded packaging materials and found out where everything went.
    • Second:Assemble most of the parts with the provided bolts. An impact drill works wonders for the nyloc bolts, just don’t tighten them down too much at this point.
    • Third: Mark the obvious top and bottom welds with Sharpie. Disassemble. Strip paint from weld locations. Reassemble. Square the frame. If you don’t know how to do this google it and you may want to reconsider if you are up to building this thing in the first place.
    • Fourth: clean / grind / paint welds.
    • Fifth: Attach the rest of the shit in the box to the frame.
    • Sixth: Deal with the bearings.
    Basically, your have to pull apart the hubs, fish out the bearings, clean everything, repack the bearings and reassemble the hubs. Don’t beleieve the hype, just buy a bearing packer to press the shit Chinese grease out of the bearings. Don’t bother with trying to “clean it out” or “just use the palm of your hand to repack the bearings”. The bearing packer costs about $25 and you will be glad you bought it. Also, to get the medial bearing out you will want to cut a small block of wood to knock it out. You will know which bearing when you get to it. If you fucked up and put a screwdriver under the lip of the bearing seal thinking you could pry it loose, you will need to replace a spring. I just bought oil seals of a similar size from AutoZone and swapped out the inner springs. Again, you will know when you have reached the part of the medial bearings. Then repack with the bearing packer and some decent grease from AutoZone or whatever auto parts dealer is closest. Wear gloves and make sure you don’t burn down the garage with greasy rags.
  • Seventh, Stick wheels onto axels. This is self explanatory.
  • Eighth, Admire work, drink beer, wire the thing up. 20140420_175258

Wooden Decking

The manual suggests using plywood. Plywood kinda sucks for a trailer for obvious reasons. It swells when wet. Actually it basically sucks outdoors. You can paint it, but it will get borked pretty soon regardless. Treated lumber is probably the best bet for decking etc in the trailer world. Home Depot now sells what looks like less poisonous treated lumber. Their sign says that it is safe for vegetables, even has a hand pulling out a bunch of beautiful carrots from fertile soil in the picture, but if you believe that this shit wont give you colon cancer than you are an idiot. But it will work for a trailer that I don’t intend to eat. All of the decking is 5/6″x6″x8′ redwood-color treated lumber from home depot. Since the trailer is pretty close to 4’x4′, 8′ long lumber is the obvious choice. I think it took around 12 or 14 boards total. The lower decking is 2×4 treated lumber.


I used all 1/4 inch bolts for all non-supplied hardware. Virtually all of the hardware was 1/4″ carriage bolts with cut washers and lock washers. This combo is cheap, more than enough strength and easy to work with. Since carriage bolts do not require washers, they grab the wood under them and sink in, resulting in smoother surface. If you are a masochist, you could try counter-sinking hex head bolts, but there are a lot of them and you will be sad if you tried. Also, non-countersunk hex heads would be a bad choice. Hinges are obvious type, same with gate latches

Deck base

The base of the deck was made from pressure-treated 2×4 boards laid across the three main horizontal members of the frame. They were bolted down on the edges and with 2x bolts in the middle of the frame. Cut out the obvious holes for the stakes. Attach with 1/4″ hardware in a manner that allows for clearance of 1/4″ hardware for decking above. This means leave space for the cut washer from the above decking so that it will fit between the bolt hole and the steel frame. Then add upper decking. Cut and install stakes. Cut and install fence rails. Build doors, install hardware. And you’re good to go. The pictures make it fairly obvious what to do given that you have done this sort of thing before. Trailer with stakes

Re-engineer the receiver

My receiver would not physically fit over my hitch ball. I think this was because I used an impact drill to fasten the nyloc bolts throughout the trailer, including the two bolts which hold on the receiver. I may have over-tightened them which caused the lip of the receiver to bind in the housing. To fix this I just took the receiver off and slipped a washer between the receiver and the trailer tow arm. Then the whole thing worked like a charm.

Finished Trailer

Trailer is ready for inspection and plating. After that I will have to build some stuff to allow the trailer to move with the back gate in a lowered state, since I want to be able to carry 2×4’s and such. The trailer will also need some plywood interior framing that is removable so I can carry dirt / mulch without it spilling all over the road. 20140427_161559


Additional Notes

One of the rear lights did not work for me initially. Turns out it was a ground fault. This is because the ground wiring for the trailer is the frame (which is pretty typical). However, since the frame is powder coated, if your nut does not scratch through enough paint during assembly of the rear lights, then the lights will not have a ground. The fix is to just scrape off some of the paint under the nut.

Leave a Reply

Your email address will not be published. Required fields are marked *

Captcha cuz spammers are everywhere! * Time limit is exhausted. Please reload CAPTCHA.