Parts Needed to Add Electric Brakes to a Trailer with a Standard 3,500-lb Axle  

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If you are wanting to add brakes to your trailer that has 3,500-lb axles with a 5 on 4-1/2 inch idler hub that fits 15 inch wheels, like part # AKIHUB-545-35-K, then you will need to upgrade to a hub and drum as there are no kits that add a drum to an idler hub.

If you do have the standard size spindle on your axle then you can very well use our Trailer Hub and Drum Assembly # AKHD-545-35-EZ-K which meets all of the criteria that you mentioned. You will need to verify what the inner bearing, outer bearing, and grease seal numbers are the same on your spindle though. If it uses the Inner bearing - # L68149 (1.378" inner diameter), Outer bearing - # L44649 (1.063" inner diameter), and Grease Seal # 58846 (1.719" inner diameter), then this hub and drum assembly is a perfect fit. If you can't find the numbers on your bearings and seal then you can use a Digital Caliper # PTW80157 to verify the measurements that I just listed for each part number. You will want to measure locations B, C, and D from the attached picture.

For a electric trailer brake kit that is compatible with this hub and drum assembly you will want to use part # AKEBRK-35-SA which mounts to a 4 Bolt Mounting Flange # 4-35 that needs to be welded onto your spindle by a professional welder. You will also need the Mounting Hardware for 10" Brake Assemblies # BRKH10B.

To finish up an electric brake setup on your trailer you will need to add some additional wiring and a breakaway kit as well. For additional wiring your can use part # HS381-9000 which comes with a junction box that you will connect the wiring from your 4-Pole to (after cutting the 4-Pole off) as well as the wiring that goes to your brakes, part # 10-1-1. This will give you a 7-Way on your trailer so that your tow vehicle can activate the brakes via a brake controller like the Prodigy P3 # 90195.

A breakaway kit, like part # 20099, is required in most states for trailers rated over 3,000 GVW. It will engage the brakes on your trailer should it come uncoupled and the safety chains fail.

Since electric brakes are the preferred route to go when adding brakes to a trailer I recommend going with this setup. However, if you would rather have hydraulic brakes just let me know and I can recommend the parts for that as well.

I have attached some videos and helpful articles that can help you with the installation process as well.

expert reply by: Jon G

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