Parts Needed to Replace Hydraulic Drum Trailer Brakes with Electric Drum Trailer Brakes

Question:

I want to convert to electric brakes. My trailer axle measures at 10x 2-3/4. 2-3/4inch from center to center. All I can find is 2- 1/4. Am I measuring wrong or do you have different size?

asked by: Sandy R

Expert Reply:

The 10x2-3/4 measurement on brakes is in reference to what drums they fit, not the mounting pattern. The 2-3/4 inch measurement you are getting is indicative of 10x2-1/4 inch brakes like # K23-478-00 that you have referenced. To measure for the size brake assembly you need you will measure the inner diameter of the drum and the width (both where the shoes/linings make contact with the drum). The matching right hand side brake assembly is # K23-479-00.

But if you have 3,500 pound axles and not 4,400 pound axles you would use # 23-468 for the left and # 23-469 for the right.

Since you are currently using hydraulic drum brakes you will most likely have to replace the hub and drum assemblies as well since not all hydraulic drums can be used with electric brakes. To get the right hub and drum assemblies and to make sure you get the proper brake assemblies I will need to know the inner and outer bearing numbers stamped into the metal of the bearings.

I will also need to know the bolt pattern of the wheels. I have included some links to the right that cover electric drum brakes and determine wheel bolt pattern for you. To use the electric brakes you will also need to do some wiring and add a brake controller to the tow vehicle. The trailer and tow vehicle will each need to have a 7-Way trailer connector.

I have linked a video showing a conversion like you want to do that you can use as a guide.