What Do I Need to Add Electric Brakes to My Utility Trailer with 3,500 Pound Axle?

Updated 12/08/2025 | Published 11/13/2025

Products Featured in This Question

etrailer Electric Trailer Brakes - Self-Adjusting - 10" - Left/Right Hand Assemblies - 3.5K

(3195)

$154.43

10 Gauge Wire - Blue Primary - Per Foot

(108)

$1.61

Trailer Wiring Junction Box - 7 Color Coded Terminals - ABS

(559)

$15.54

Bright Way Trailer Breakaway Kit with 0.5-Amp Charger and 5 Ah Battery

(438)

$65.74

Easy Grease Trailer Hub and Drum Assembly for 3.5K Axles - 10" - 5 on 4-1/2 - Pre-Greased

(1840)

$100.26

Deka Heat Shrink Butt Connector - 12-10 Gauge - Nylon Insulation - Yellow - Qty 10

(1151)

$13.21

Hopkins Deluxe Trailer Wiring Installation Kit

(24)

$27.74

Question:

Hi. I have a utility trailer 1 axle that I am thinking of installing brake system. What do I need? Thanks

asked by: Javier A

Expert Reply:

Hello Javier,

Happy to get you the parts needed to add electric brakes to your utility trailer. You asked the question on the 3,500 pound brakes, so I am assuming that you have a 3,500 pound axle. Please check your axle tag, if it is rated for something other than 3,500 pounds please let me know.

You will need to upgrade your idler hubs to hub and drums, if you have a 5 on 4 1/2" bolt pattern you will want to order (2) of the Easy Grease Trailer Hub and Drum Assembly for 3.5K Axles - 10" - 5 on 4-1/2 - Pre-Greased # AKHD-545-35-EZ-K.

I am sticking with your brake choice, the etrailer Electric Trailer Brakes - Self-Adjusting - 10" - Left/Right Hand Assemblies - 3.5K # AKEBRK-35-SA. These are self adjusting, after install please make sure to break them in properly. I attached a help article on how to do it the correct way, it will be step 4.

You will need to run brake wire, the 10 Gauge Wire - Blue Primary # 10-1-1 is sold by the foot. I like to run the brake wire from the front of the trailer to the driver side brake, then take the brake wire along the axle tube to the passenger side brake. Make sure you use zip ties to secure it well.

You will also need a breakaway kit, the Bright Way Trailer Breakaway Kit with 0.5-Amp Charger and 5 Ah Battery # 3802339 will get the job done.

If you do not have the tools for the job, the Hopkins Deluxe Trailer Wiring Installation Kit # HM51020 is a great kit. I prefer to use the Deka Heat Shrink Butt Connector - 12-10 Gauge - Nylon Insulation - Yellow - Qty 10 # DW05745-10 on the wiring however, the heat shrink provides a great seal so water can't get in.

If you have a 4 flat currently on the utility trailer, you will need to cut that one off and install a 7-way, the 7-Way Molded Trailer Wire Connector, 4' Long # H20043 is a great option. I like to wire mine all to a junction box, I really like the Trailer Wiring Junction Box - 7 Color Coded Terminals - ABS # 3375601101 because it is color coded.

Last but not least, you will need a brake controller if you do not have one already. If you do not have one, please let me know the year, make, and model of your vehicle so I can find the best option for you.

I have attached a help article on adding electric brakes to a trailer that I think you will find most helpful.

Do you use this utility trailer mainly for fun, or for work?

expert reply by: Kate F

Wiring Kit All Pieces Included
(click to enlarge)

Kate F.

12/8/2025

Hey Javier, how did things go with adding the electric brakes to your utility trailer? Did the hub and drum assemblies and wiring setup work out as planned? Your update could make it easier for others tackling the same upgrade.