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Parts Needed To Install Electric Trailer Brakes On a 3,500LB Idler Hub Trailer Axle


I have idler hubs on my trailer now and want to convert to electric brakes. I removed the hubs ,5x5 1/2, and measured the spindle. Came up with 1.059 inner bearing, 1.374 outer bearing. Can you give me direction to a complete hub and drum assembly? I also measured the axle itself and it is 2 3/8 diameter which I believe makes it a 3500 lb. axle.


Helpful Expert Reply:

Those measurements are consistent with a 3,500LB axle. I do recommend verifying the grease seal measurement as well as I have seen trailer axles that use a slightly smaller inner diameter Grease Seal # 168255TB(1.687"). If your grease seal landing measures 1.719" then the kit I recommend below will have all the correct components.

You will need a Brake Flange # 4-35 on your axle. If you do not have one the axle should be taken to a shop to have this flange welded on as they will have the correct jigs to ensure the plate is positioned correctly. This will accept the Electric Trailer Brake Kit # AKEBRK-35-SA(qty 1). These are self adjusting brakes so you will not need to manually adjust them over their life which will give you more consistent brakes and better life of the brake shoes.

The Trailer Hub and Drum Assembly # AKHD-555-35-K(qty 2) comes preloaded with bearings and the grease seal. It includes lug nuts and a grease cap for a standard axle. If your spindle has a grease zerk for EZ lube you will need the Easy Grease Trailer Hub and Drum Assembly # AKHD-555-35-EZ-K(qty 2). This is the same as the other hub but includes the grease cap with rubber insert to easily access the grease zerk. The Bearing Buddy Bearing Protectors # BB1980A-SS can be used if you do not have a grease zerk but want the convenience of an EZ lube axle.

For the wiring you will need the etrailer Trailer Wiring 7-Way Upgrade Kit w/ Junction Box # e99011 with a Hopkins Engager Push-To-Test Trailer Breakaway Kit # 20400. Then 10 Gauge Wire # 10-1-1 sold by the foot, to run to the brakes on the axle.

I have linked one of our help article pages below on adding electric brakes that would be good to review.

helpful expert reply by:
Gregory M

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