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Parts Needed To Add Brakes To Single Axle Boat Trailer  

Updated 11/04/2025 | Published 01/14/2025



Question:

I have a single axel Eagle boat trailer. I would like to add electric brakes to it. Can you advise on what I need . Thanks

0

Expert Reply:

Hey Steven, thanks for reaching out. It may be possible to add brakes to your trailer. The first thing you will want to verify is that your axle has a brake flange. It should look something like part # 4-35. If no brake flange is present, they can be welded on by a shop, or you can replace the axle entirely.

If you do have a brake flange, this means brakes can be added. From there I will need to gather a bit of info from you. I will need to know the weight capacity of your axle, as that will help us choose the correct brakes. most commonly for single axle trailers we see the 3.5K brakes like part # AKEBRK-35-SA which are 10" x 2-1/4" shoes.

I will also need to know your spindle size/bearing sizes to determine the correct hubs. Knowing the weight capacity does help to narrow this down, but your best option here will be to pull one of your hubs and remove the bearings. Each bearing will have a number stamped on the edge, or you can measure the ID with a micrometer. Once we know that info we will be able to pair together the correct brake assembly and hubs for your trailer. If your axle does happen to be the 3.5K capacity like I mentioned above, you would use the # AKHD-545-35-EZ-K hub which is standard for 3.5K axles. It uses the # L68149 (1.378" inner diameter) inner bearing and # L44649 (1.063" inner diameter) outer bearing. Please check your hubs to confirm your baring sizes.

Once we have your brakes and hubs down, you will just need a 7-way wiring harness like part # e99011 plus additional wire for your lights and brakes. You will also need an emergency breakaway kit like part # 3802308, as well as an electric trailer brake controller for your tow vehicle.

If you want to confirm your axle capacity and bearing sizes for me I am happy to confirm fitment for those parts. I have linked an article for you below that goes over how to add electric brakes to a trailer in more detail. Comment below with that info or if you have any questions on any of this. Cheers!

expert reply by:
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Jesse M
Jesse M. profile picture
Etrailer Expert

Jesse M.

11/3/2025

Hey Steven, how did things go adding the electric brakes to your Eagle boat trailer? Did the 3.5K brake assemblies and hub setup end up matching your axle and bearings? Your update could make it easier for others looking to add brakes to a similar trailer.

Steven S. profile picture

Steven S.

11/3/2025

@JesseM yes they worked fine
Jesse M. profile picture
Etrailer Expert

Jesse M.

11/4/2025

@StevenS That's awesome, Steven. Thanks for sharing! Glad to hear it all worked out. Feel free to come back anytime you need anything! I am just a click away!

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