Parts Needed To Add Electric Brakes To A Boat Trailer

Updated 01/11/2022 | Published 01/10/2022

Products Featured in This Question

Dexter Electric Trailer Brakes - 10" - Left/Right Hand Assemblies - 3.5K

(1556)

$167.49

Hopkins Engager Trailer Breakaway Kit w/ Charger, LED Tester, and 5 Ah Battery - Side Load

(746)

$60.86

U-Bolt Kit for Mounting 3,500-lb, Round Trailer Axles - 5-1/2" Long U-Bolts

(1998)

$68.08

Mounting Hardware for 10" Brake Assemblies

(416)

$18.18

Wiring Kit for Hydrastar Electric Over Hydraulic Actuators

(12)

$83.84

Dexter Trailer Axle Beam with EZ-Lube Spindles - 89" Long - 3,500 lbs

(785)

$233.33

Spring Seat for Typical 3,500-lb, Round Trailer Axles with 2-3/8" Diameter

(637)

$16.31

Question:

I have a boat trailer from the early 90s with a square tube axle 2 inches wide, 82 1/2 inside from inside 4 bolt flange to flange and 71 1/2 from center of spring to center of spring mount. I need to replace this axle as it is rusted through at the leaf spring mount on one side. I would like to change it to electric brakes, can you help?

asked by: Kevin W

Expert Reply:

Adding brakes to your boat trailer is definitely possible, but it will require a few things. First and foremost, you will need to change to a round axle. Square axles typically are not designed to have brakes installed on them, so there will not be a way to stay with it. Since your axles is in a bad way and needing replacement anyway, this is definitely good timing.

With that said, I recommend going with the Dexter Trailer Axle # T3584F-EZ-8974. The width measurement for the flanges is almost spot on (82-5/8"), but the spring seats will measure 74" from center to center, so they will need to be removed. The # TRSS238 spring seats will then need to be welded on at the correct locations. As this is a round axle, you will also need to change to the U-Bolt Kit # APUBR-1. I do also need to note that the hubs/drums are not included and you will need two of the # 84546UC3-EZ hub/drums, which have a 5 on 4-1/2 bolt pattern. If you have 4 bolt wheels, they will need to be upgraded to match the hubs/drums as well. The # 23-26-27 electric brakes and # BRKH10B mounting hardware will complete the axle.

Now for some electrical parts. You will of course need to wire the brakes up and having the Trailer Wiring 7-Way Upgrade Kit # HS381-9000 makes this significantly easier. This includes a 7 Way plug so you will not need to add this on. You will also need a break away system, like the Hopkins Engager Push-To-Test Trailer Breakaway Kit # 20099, which will engage the brakes automatically if the trailer every becomes disconnected from the vehicle. You will of course need various lengths of wiring and butt connectors to complete this.

The last thing you will need to do is upgrade the connector on your vehicle to a 7 Way and add a brake controller. If you already have these, you will be good to go.