Question:
I have a 1989 Calkins boat trailer with 6 bolt 15 inch wheels and wondering if a conversion from drum brakes to rotors is possible
asked by: Marc L
Expert Reply:
Yes, it should be possible to upgrade your 1989 Calkins boat trailer with 6 bolt 15 inch wheel over to disc brakes from drum brakes. The first thing you will need to do is determine the bolt pattern of the wheel, see video on how to correctly measure, and then you need to determine the inner and outer bearing part numbers, and the seal part number to select the right disc brake hub and rotor combination.
Once you have the bearings for your spindle and the wheel bolt pattern figured out, you will need to select a disc brake kit, see link, that will match. Most likely you will need a kit for 6 on 5-1/2 inch wheels and 25580 inner bearings, 15123 outer bearings and RG06-070 seal. If all of these match, you can use the Kodiak Disc Brake Kit, # K2HR526D.
You will then need to make sure that the hydraulic actuator coupler on your trailer can be modified for use with disc brakes, or select a new hydraulic actuator that is compatible with disc brakes and will fit on your boat trailer tongue. You also need to make sure the ball size is compatible with your towing setup. The Titan Zinc-Plated, Leverlock Brake Actuator, # T4715400, would be a good choice if your trailer is below 6,000 lbs gross weight, loaded and ready to travel, and the 2 inch ball size is correct.
I have linked a photo that I put together showing all of the parts needed to convert over to hydraulic disc brakes and a video showing the installation of a brake actuator coupler on a trailer.
expert reply by: Bob G

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Products Referenced in This Question
Titan Zinc-Plated, Leverlock Brake Actuator - Disc - Adjustable Ball - Bolt On - 6,000 lbs
Product Summary:
Brake Actuator Coupler
Bolt-On
No Lockout
Disc Brakes
6000 lbs GTW
Product Specs:
Straight Tongue Coupler
1-7/8 Inch Ball Coupler
2 Inch Ball Coupler
Product Page this Question was Asked From
Kodiak Disc Brake Kit - 12" Hub/Rotor - 6 on 5-1/2 - Dacromet - 5,200 lbs to 6,000 lbs
Product Summary:
Disc Brakes
Kit with Hub and Rotor
15 Inch Wheel
16 Inch or Larger
6 on 5-1/2
Product Specs:
5200 lbs Axle
6000 lbs Axle
Conversion for Drum Trailer Brakes to Kodiak Disc Brakes on a 1989 Calkins Boat Trailer
Parts Needed to Add Trailer Brakes To a Trailer with No Existing Braking System Installed on It