Replacing Old 3 Bolt Trailer Brake Assembly on 3500 lb Axle  

Question:

Expert Reply:

The only 3500 lb brake assemblies we offer are compatible with a standard 4-bolt backing plate, which leaves you with a few options.

If you can find somebody local that's familiar with trailer axle work, you can have the existing brake assembly mounting flange removed and a new one welded in place. A 3500 lb axle typically has a 2-3/8 inch diameter axle tube. If that's the case with your axle, you'd want to use # 4-35. The mounting flanges need to be welded in place so they're perfectly square in the correct position so the brake assembly makes the proper contact with the hub/drum, so this isn't a good project for a hobbyist welder.

Another option would be to replace the axles. We offer a couple of the more common axle lengths. To see if the axles we offer would work, you'll need to measure the hub face to hub face length of your existing axle along with the distance between the center of the spring perches. If the hub face to hub face dimensions of your axle is 89 or 95 inches and the spring perch spacing center to center is 74 or 80 inches, we do have axles that'll work. If the perch spacing isn't exact, you can always cut off the existing ones and add some in the proper location, but the hub face to hub face distance needs to be about exact. I've linked to our selection of 3500 lb axles.

The replacement axles have spindles compatible with a L44649 outer/L68149 inner bearing so you might need to replace your existing hubs with # AKHD-550-35-EZ-K which is compatible with a # AKEBRK-35L left and # AKEBRK-35R right brake assembly.

I realize this is a lot of information to take in, if you have further questions, feel free to let me know and I'd be happy to help further.

expert reply by: Mike L

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