This Old Trailer: Changing Hydraulic Trailer Brake to Electric

Converting Hydraulic Trailer Brake to Electric Brakes on This Old Trailer

Today on This Old Trailer we are going to replace hydraulic brakes with electric brakes. Basically it is going to be a matter of taking off the tires, removing the hubs, go ahead and removing the backing plates and drain the hydraulic lines of fluid, and then going ahead and bolting on the new brakes. We will start off, obviously, by taking the wheels off. OK, go ahead and remove the dust cover here. It is an E-Z Lube spindle so this has a tang washer that we need to bush back down so we can unlock the castle nut right here. Just push it back down. Now we should be able to take the hub right off. The next task is to go ahead and disconnect the hydraulic lines. We have that disconnected. Now we need to pull the clip out so we can release this part here. And that is just a little piece of metal right here that you can just pry out. Alright, now we can unbolt this at the back of the hydraulic backing plate. Alright, now we can unbolt the backing plate from the flange on the axle. Now we are down to our bare axle. We will clean it up a little bit and then reinstall the brakes. 1:24

Before we put on our brake, we are going to cover which way it goes. Now it says on here right side, which is also the passenger side. But if you do not have the sticker or it is messed up, this bow right here, think of it as an arrow that points to the front always. We will just go ahead and flip it over. Get the wire. So go ahead and put our wire holder. It just loops over and pushes into place. It keeps it out of the way so it does not get smashed in the plate there. And we will go ahead and wire these up in a little bit. We will just slide it on because it has existing studs. And the magnet also points to the bottom always. Before we actually bolt it down, you might want to take a test fit and make a sure you have enough room for the lock nut and washer when you put it together. If you do not have room for it, you can get by by using just the nut. But, it might be a good idea to go ahead and use some Loctite on there to help ensure that it stays on. And we are going to be using part number LT37643. Alright, now this Loctite material what it does is it basically locks the nut onto the bolt. And what happens is it stays in this pliable state right now but as soon as you run a nut down on to it this air squeezes out and it starts hardening up. It basically turns into like an inside lock nut. And you can also easily undo it with basic, common hand tools too. 2:35

We will just go ahead and install our brake assembly and we will go ahead and install the nuts. What is also nice about the Loctite is it makes it a little bit more easier to thread on. Once you get everything snugged down, torque them down about 1/8 of a turn. That should be just fine. Now, we have two wires coming out of the backing plate. Now, we are going to ground one of them and then, since it is a magnet, it does not care which one as long as one goes to secure ground. We are going to put a ring terminal on the end and put it about right here. That way, you have plenty of room for the wire to go up and down as the suspension goes up and down. We will go ahead and run this wire back up to the front at a later point. Let us go ahead and reinstall our original hub. We can reuse the original hub because it has a flat surface on the inside and that it where our magnet will ride against this. So all we have to do, really, is to inspect the seal. Make sure it is in good shape and, if there is any doubt whatsoever, go ahead and replace the seal. We will go ahead and clean this one up and inspect it and then we will replace it if necessary. At that point, we can go reinstall the hub. Push our hub back into place. Make sure your bearing is seated. Alright, we will go ahead and pop on a new tang washer. It is always a good idea to replace it, just like a cotter pin. Reinstall a castle nut and we will run this down until it stops. Kind of rock it back and forth a little bit. Spin the hub a little bit. Make sure everything is seated. And run it down until it stops and then back off to the next notch, whichever you can use one of the tabs on the tang washer for. And then just spin it back down. 4:29

And then we can reinstall the dust cap. Now we are going to be using a special tool for that. That is going to be part number 290-991. Get it started. Tap it into place to hold it. Put our tool over it and then just tap it into place. Alright, now we will go ahead and adjust our brakes. We are going to pop off one of the covers here so we can see the adjustment dial on the inside. We are going to use a brake adjusting tool, available at any auto parts store. And basically, what we are going to do is adjust it until we can lock it up and keep spinning the hub until you cannot do it by hand anymore. Once you cannot move it by hand anymore, go ahead and back it off about ten clicks. OK, one hub is complete. Now we will go ahead and do the same thing for three more. Alright, now with all of our hub assemblies installed and grounded, we will go ahead and run our power wire. We are going to use a 10 gage wire to run from the front to the back. We are going to follow the original line where the brake line used to go to make things easy. Now we ran our wire from the front and we are going to the back wheel right here. We are going to make our permanent connection to this one wire. And then from this main blue wire, we are going to make our jumpers to the rest of our hubs. We are just going to use a butt connector to make our first connection here. Now, our other wire is going to be a lot thinner gage obviously. So you want to make sure you tighten it up really tight and maybe fold it over to give it a little bit more grip on it that way too. And then crimp it down. Alright, now that is our first connection. Now we will make a jumper from this wire and go to the other side of the axle for the other brake assembly. Alright, we will make the same connection as we did before. Alright, now let us go back to our original wire and make our connection there. 6:22

And now we are going to make our connection here. Now there are a variety of connections you can make. You can use a wire nut, solder and, in this case, we are going to use a quick splice which is designed for this size wire, so we are good to go there. We have our back axle done. Let us go ahead and go to the front axle and repeat the same process. And we are going to make our jumper right across here. And we will use a quick splice for that too. Then we will go back on across. OK, make sure you have plenty of room. Now we are leaving this loose for now. We will go ahead and attach these to the floor for a permanent install once we get done routing the wires. And while we are at it, we will go ahead and tape up our connections. At this point now, we can go ahead and zip-tie our wires to put them wherever we want. Probably use some loom clamps and we should be good to go. Then all we have to do next is go ahead and put the 7-pole on the wire up front. So now we will just go ahead and get rid of our 4-pole. And we are going to add our 7-pole to it. We are going to take apart the 7-pole and run it through the inside out. Put in our four wires for our lights and our ground and then we will run our blue wire from our brakes. Then we are going to strip these and install ring terminals to make our connections to the 7-pole itself. Go ahead and hook up our wires to the 7-pole. Now it is not going to be color for color on a few of them but it will be, in this case, blue to blue because blue will be brakes on the 7-pole. We are going to hook up the right turn and that is going to be green on trailer wiring and on the 7-pole it is going to be brown. Now we are going to do our brown wire which is running lights and it will be green on our 7-pole. Yellow is going to be left turn on our wire harness and it is going to be red on the 7-pole. With our white wire with the ring terminal we will go ahead and attach it to the ground here. And we will just go ahead and put the loom back into place. Let us go ahead and put the wheels back on and then we will apply power and give it a shot and see what happens. Alright, we got it to spin. Let us go ahead and apply power, a full 12 volts, and see what we get. Want to hit it. One more time. Off. On. And there you have it for converting This Old Trailer from hydraulic brakes over to electric brakes.