How to Convert Hydraulic Surge Brakes on a Trailer to Electric

Check it out before you haul!

This is not too hard a job but you do need to do research for it to work.

Things You'll Need

• mechanics tool
• electrical tools
• jacks

Instructions

1. 

   If this is a boat trailer you may want to stay with hydraulic. Electric brakes will need to be treated with more care and may need more maintenance than hydraulic because of getting submerged in water. You shouldn't leave electric brakes under water for long periods of time so you need to not leave your trailer sitting in the water while you are out boating. That being said.
   First you need to Identify the size and type of your wheel hubs. If you are going to take your time and do this in steps go ahead and start taking things apart. Remove the wheel then the brake hub will be exposed.
   They are most likely drum brakes as apposed to disc brakes. Here you will find that out.

2. 

   If you have hydraulic disc brakes You will most likely have to change to drum brakes. I don't know of any disc brake electric kits for trailers but they could be out there. New products come out at all times so check the web.

3. 

   There are many kits available and they will be able to help you match them to your trailer. Make sure your rims will fit the new drums. Now that you have identified which type you have you will need to search for a suitable replacement.
   There are laws concerning trailers with brakes so you will have to convert the emergency breakaway kit also. It operates the brakes automatically if the trailer comes loose from the vehicle. You will need a separate battery mounted on the trailer for this device. The brake kit should explain that.
   Take pictures of what you have so you can use them as a guide. Clean up all the old parts for one wheel on each side so you can use them as a guide.

4. 

   When you remove the hydraulic lines watch for fluid draining out so it does not spill on the ground. You can most likely follow the same route to run the electric wires that will be replacing the brake fluid lines.

5. 

   You will be replacing the hubs all the way to the axle so you will get new bearings with your kit and instructions on how to install everything.
   Your kit should have shoes, also included. There are specialty control kits that go along so you might want to check those out depending on how modern your vehicle is and the needs of your hauling. They monitor your braking and adjust accordingly.

6. 

   Lets go to decisions have been made and parts have been purchased.
   The complete assembly will be ready for electrical hook up and will tell you the best place to make your connection. Most will go to the brake light and running light plug but don't worry, a kit will come with a plug for the trailer and probably a matching plug for the vehicle. Any changes that have to be made to the vehicle wiring will be in the kit instructions. If you don't use a kit you will have to be more creative. You can use the existing plug for the lights and wire a new plug for the brakes. The new plug will either wire to the brake light wire at the rear of the vehicle or the brake light sensor under the hood. Some used brake light connections might not be very reliable so make sure you have a good connection whichever route you choose. You don't want a loose brake light connection to equal infrequent brakes nor do you want a running light cross connection to equal constant brakes. Here you need to make sure you have good and independent connections.

7. 

   Use the instructions in your kit for mounting the new hubs. When all mechanical parts have been installed check for freewheeling. Spin the wheel and make sure nothing is dragging. It should turn freely or with a slight drag but still can be turned easily with your hand. Shoe brakes will have an adjusting lug that you turn with a screwdriver or a wrench it may look like a star and as you turn it the brakes tighten or loosen. You don't have this with disc brakes.

8. 

   Use a 12 volt battery with jumpers, not jumper cables but small alligator clips hooked to about the same size wire as the new ones you ran for the hookup. Hook the ground clip on the frame then momentarily touch the positive clip to the hot side of the wiring either at the wheel or have your helper do it at the plug. You should see or hear the brake (solenoid) cylinder operate. Do not do this if everything is not in place, in other words everything is mounted except the wheel. If you do this any sooner things can fall apart that will be extremely hard to put back together

9. 

   Use the above method to check all (solenoids)cylinders. With the connection "made" , you should not be able to turn the wheel hub at all. When satisfied put the wheel on and try again. This is of course with the trailer up on blocks so you can spin the wheel. If you can turn the wheel by hand when the connection is made you need to adjust or make sure the pads are properly in place. With the connection off it should turn easily but not coast round and round.

10. 

    When everything is in place and the wheels are on take it for a test spin without the boat or load and with your helper following in another vehicle.
    It should stop smoothly with no pulling to either side. When you get back you can look for smoke or funny smells around the wheel. You will be able to tell if they are too hot. The instructions should have guides to correct this but basically it is just checking or adjusting.
    If their stuff doesn't help remember to raise the wheel and spin while someone operates the brakes. Make sure the brake isn't staying on all the time. You have both mechanical and electrical to check. Don't assume it is one or the other. If you unplug the wire from the vehicle and the brakes are still on you know it is mechanical. If you plug the wire back in but no one is mashing the brakes you know it is electrical.

11. 

    After making the fixes try it again. Then after the empty trailer passes the test try it with the boat or with a load in the trailer. Bet everything works now.
    Happy "trailering"!

Tips & Warnings

• Use a helper.

• Make sure your tires and rims will fit new hubs.

• There are some federal laws to consider.