Understanding Trailer Brake Replacement

Trailer brake replacement on a spring axle assembly can seem daunting, but with the right tools and steps, it’s a manageable task. To help you through the process, here's a step-by-step guide to replacing an electric brake on a spring axle assembly 

1. Removing the old brake assembly
2. Installing the new brake assembly
3. Wiring and reassembly
4. Final Steps 

• Lift the Trailer Safely: Always lift the trailer by the frame, as specified by the manufacturer. Never lift it by the axle or suspension components as they are not designed to bear the trailer’s weight. Make sure the frame is properly supported before you start working under it.
• Remove the Wheel: Begin by removing the lug nuts holding the tire in place. Use an impact wrench, but ensure the socket comes to a complete stop before moving to the next lug nut to avoid rounding the corners. Remove the tire and set it aside. 

1. Dust Cap and Cotter Pin: Use a flat head screwdriver to remove the dust cap from the hub assembly. Rotate and pry around the edge until it comes free. Next, use needle nose pliers to straighten and remove the cotter pin. Discard the cotter pin as you will replace it later.
2. Castle Nut and Spindle Washer: Remove the castle nut by hand, followed by the spindle washer. You can use a flat head screwdriver or rock the hub assembly back and forth to pop the washer free. Hold the hub assembly to prevent the bearing from falling out, then remove the hub from the brake assembly.
3. Cutting Wires and Cleaning: Cut the power and ground wires leading to the brake magnet. Clean all grease off the spindle with a clean rag.
4. Remove Brake Assembly: Remove the nuts and lock washers holding the brake assembly to the axle and spindle. Note that hardware may vary with different axles. Remove the old brake assembly.

1. Install New Brake Assembly: Ensure the bolt pattern and orientation of the new brake assembly are correct. Reinstall the hardware, securing the brake assembly to the axle beam and spindle. Each bolt should get a locking washer and nut. Start each nut by hand to avoid cross-threading. 
2. Tighten and Torque: Tighten the nuts to seat the brake assembly. If using an impact wrench, ensure the socket is completely stopped before moving to the next nut to avoid damage. Use a torque wrench set to 35-55 foot-pounds to ensure each nut is properly tightened until you feel a click or pop. 

1. Reconnect Wires: Reconnect the power and ground wires using 3M Scotch locks. Crimp securely to ensure good connections.
2. Hub Assembly: Reinstall the hub assembly, ensuring the outer bearing and bearing washer are in place. Install the castle nut by hand to avoid cross-threading. Use the torque wrench to set it to 55 foot-pounds. Loosen the castle nut slightly with a breaker bar, then re-tighten finger-tight. Secure with a new cotter pin and bend it to keep it in place.
3. Dust Cap and Tire: Gently tap the dust cap back into place with a rubber mallet in a circular motion. Re-mount the tire, aligning the holes with the lug nut studs. Hand-tighten the lug nuts to prevent cross-threading. 

1. Tighten Lug Nuts: Tighten the lug nuts in a star pattern using an impact wrench, ensuring the socket has stopped spinning before moving to the next nut. Lift the chassis off the jack stands, remove the stands, and lower the frame back down. 

2. Torque Lug Nuts: With the tire on the ground, use a torque wrench to tighten each lug nut to the manufacturer's recommended specs, following the same star pattern. Check and re-torque the lug nuts after 10, 25, and 50 miles, and periodically during regular maintenance. 

By following these steps, you can replace the electric brake on a spring axle assembly confidently and safely, ensuring your trailer is ready for the road ahead. 
 
Need more help with your spring axle brake replacement? Visit our support site for expert guidance! 

Disclaimer: These photographs, recommendations, and approximations are intended for demonstration purposes only and do not reflect the specifications of any particular tow vehicle, recreational vehicle, or trailer. Always consult the manufacturer’s Owner's Manual.