3 Horse trailer refurbishment

3 Horse trailer refurbishment

We purchased a 3 horse trailer about a couple of years ago to move our 2 thoroughbreds around. The previous 2 horse trailer was too small for our horses. I had refurbished the 2 horse trailer before selling it, and it turned out well. So, purchasing the 3 horse trailer that needed a lot of work wasn’t that big of a deal. We had used this trailer in the past so knew what it needed.


Good Bones

The 3 horse trailer is a all steel construction, and while it is heavier than a newer trailer with aluminium it will hold up a little better if something bad should happen on the road. What that also means, RUST! This trailer had not been taken care of except for the basics; the floor wasn’t rotted, the metal was in decent shape, and the wheel bearings were in good shape. There wasn’t a panel that didn’t have surface rust though, the electrical was sketchy, and the brakes didn’t work. Nothing that could not be fixed.

Quick Project

What started as a quick project for rust abatement and operational soundness escalated into so many other things.

Paint – Interior & Exterior

While the exterior was bad, the interior was worse. Years of horses scrapping their teeth, rubbing/kicking the panels and dividers, and bodily functions took its toll on the paint and panels. I was just going to do a quick spray over the rusty parts with some enamel tractor paint that I had from another project. The more I worked on it though the more it grew into a full respray of the interior. I started with rattle cans for primer and top coat, but soon broke out my spray gun and went all out. Of course, before laying down the primer the panels had to be run over with a wire wheel on a grinder. Much of the old paint flaked off and the rusty spots were taken down to bare metal.

The exterior rust spots were treated with a wire wheel as well, but only the spots were primed and painted, granted some of the spots were large. I did choose a newer white that was closer to that of our truck for a future respray of the whole trailer. The biggest difference was on the rear doors, once the seam sealer was put on they almost looked new.


When we used this trailer when the previous owner was in possession, the brakes didn’t work. We had to use a ‘special 5 to 7 pin adapter’ so that the brakes wouldn’t get any power. We found out why when we used a different adapter and the brakes started smoking on one of the axles. Plus there was a rattling sound coming from one of the wheels.

Taking apart the wheels and checking the bearings and brakes showed that on one axle the brake adjuster spring had broken and the adjuster parts were rattling around in the hub. No major damage, so the adjuster parts were replaced. Also one of the hub seals was bad on the other axle, which ruined the brake pads. After looking at replacing the individual brake parts, it was just cheaper and faster to replace the back plate which came with all new parts including a new magnet for the brakes which was worn but still usable. This ties into the electrical issues.


The pigtail was the first thing that I wanted to fix. I don’t like using adapters since they add a point of failure. So, I replaced the old 5 pin with a new 7 pin RV style pigtail. Since I was doing this work and had experienced the pain of hard wiring everything and finding a mistake, I also installed a junction box for the wiring. It provides an easier way to troubleshoot and rewire if needed, plus I can power the trailer electrics with a battery for testing. After tracing out all the wiring, including the brakes, it was easy to hook everything up in the junction box.

Many of the marker lights were not working, dim, or faded so they were replaced with new units. The tail lights were working, but since they were incandescent bulbs and fixtures from 1993, they were replaced with new direct replacement LED units which work much better. Did I mention that this project got out of hand?

The interior stall area had only lighting by the doors at the rear of the trailer, and having to use a flashlight or head lamp is not always easy with horses. So I installed some LED  lights in the stall area to help. I also have some LED lights for outside the loading doors that I haven’t installed yet. The license plate holder was moved to the top of one of the loading doors where it will not get damaged, the old mounting point was in a spot where the loading door would hit it every time the door was opened causing damage.


Sadly in 1993 there weren’t as many safety requirements for trailers, but the desert weather is no friend to any plastic or reflective part. All of the reflective tape, what little there was of it was removed and replaced with DOT certified reflectors and DOT-C2 reflective tape was installed per FMSCR requirements. Safety first!


The mats on the floor were old and didn’t fit very well. The mats int he front stall were cut in such a way that the horse was standing on at least 3 different pieces of mat and when they pawed at the floor the mats would shift and ride up on each other. So the mats were replaced and cut in such a way that each set of the horses legs are on only one mat. When they move around now the mats stay put.


The changing/tack room has a RV vent which during a 60 mph wind storm the cover broke off, shattered to be more precise. I tried to use one of the ‘universal’ replacements but it did not fit well or even seal. So I found the direct replacement and removed the old unit. Well it wasn’t a direct replacement, I had to drill new holes for the mounting. Squeezing through a 14″ x 14″ hole to drill the holes was not fun in 110 degree heat.


All of the screens but one were torn or missing. I replaced the screen on one window in place, then chose to remove the windows instead. Each window is held on by 4 rivets, so drilling out the old rivets and removing the window was simple. The screen material went in quickly with the exception for the rounded corners, but after a few windows even the corners became easier. I did have to get new caps that cover the rivets, most of the old ones broke when removed. Also, new weather stripping was installed on the stall drop down windows.


The project is not quite done, but the trailer is much more safe and serviceable than it was previously. Even the brakes work properly now. The inside looks like a new trailer, the outside is a good 50 footer. I still have to put mats on the walls, but that will have to wait until some more money comes our way.

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