Summer Maintenance Tip: How to Replace Your Electronic Drum Brake


Summer is in full swing! With temperatures reaching over 100 degrees in some parts of the country, the last thing you want is a roadside delay due to the brake system on your trailer. To avoid getting stuck on the side of the road, follow this step-by-step maintenance guide to replace your trailer’s electronic drum braking system.

First Step.

Begin by removing the tire and the grease cap. To remove the grease cap, turn the hub while striking the grease cap with a mallet using a downward motion. You’ll then need to remove the nut retainer using a flathead screwdriver to pry it off. After the nut retainer is off, remove the cotter pin and the spindle/castle nut by using your fingers, turning it counter-clockwise. Next, you’ll want to remove the flat washer and inner bearings, and then wiggle the brake drum off and remove all excess grease from the spindle shaft.

You’ll reuse the cotter pin, washer, and spindle/castle nut.  Keep in mind that when replacing the entire assembly kit, you’ll need to cut the wire at the back of the plate.


Second Step.

After you’ve removed the brake drum, you’ll notice that the brake assembly is attached to the axle. Grab your ratchet and remove the nuts and washers holding the assembly together. After removing the nuts and washers, you’ll want to pull the brake assembly off. We recommend cleaning the axles off as well as treating any area that may be rusted.


Third Step.

Put the new Brake Assembly Kit on the appropriate axle. Remember that left assemblies go on the left side and right assemblies go on the right side. Most assemblies will have a sticker that marks them either as right or left assembly.

Hint: The shorter shoe goes toward the tongue of the trailer and the magnet swings to the back of the trailer.

After you’ve placed the brake assembly kit on the appropriate spindle, you’ll need a ratchet to re-attach the assembly, using the nuts you removed earlier. Tighten the assembly in place using lock washers as recommended.  Strip the wire that runs through the axle, and then reconnect the wires using a butt connector.  Note that most assemblies allow you to attach either wire from the axle to either wire on the new assembly.  Be sure to seal the butt connectors with a lighter or a heat gun.  Attaching electrical tape over the top of the butt connectors will create additional protection for the wires, but this is optional.


Fourth Step.

From here, you’ll want to place the grease packed inner bearings into the center of the drum or hub. Set the new grease seal in place using a mallet and a wooden block wrapped in a clean cloth, and then tap to seal until it’s flush with the edge of the hub. When the grease seal is in position, slide the drum back on the spindle.


Fifth Step.

The bearings should be packed in grease approved by the axle manufacturer. To ensure that the spindle washer is in place, tighten the spindle nut and then use your hands to tighten it again. Finally, snap on a new nut retainer.

For E-Z Lube axles, use a grease gun to pump grease into the assembly while spinning. Stop pumping when the grease starts to come through the bearings.


Sixth Step.

Be sure to get an even strike to press the grease cap into the hub. A cloth-wrapped wooden block and a mallet are good tools for this process.


Seventh Step.

Spin the tire while it’s still jacked up. You should feel some resistance. If there’s no resistance, use a tire tool to spin the gear adjuster until some resistance is felt.

Overbilt Trailers specializes in manufacturing custom built trailers. For more information give us a call at 1-888-687-2458.