How to Replace Drum Boat Trailer Brakes

The drum brakes on the rear of the boat trailer are designed to stop the rear wheels from turning by applying friction to the inside of the brake drums. The drum brake assembly on the boat trailer consists of an inner and outer brake shoe, brake shoe return springs, brake shoe return spring clips, wheel cylinder and the brake shoe adjuster. All of these rear braking components work together to stop the rear wheels from turning. Always replace the brake shoes before the shoe material thickness reaches 1/8 inch.

Instructions

1

Pull the boat trailer onto a flat surface and unhook the boat from the ball hitch. Make sure that the boat trailer is level.

2

Loosen the lug nuts from both rear wheels about one-quarter of a turn counterclockwise with a tire tool.

3

Jack the driver side rear of the boat trailer up with a jack and place one of the jack stands under the rear axle. Make sure that the jack stand is at least twelve to sixteen inches from the back side of the wheel hub assembly. Lower the boat trailer onto the jack stand and remove the jack.

4

Jack the passenger side rear of the boat trailer up with the jack and place the other jack stand under the rear axle about 12 to 16 inches away from the back side of the wheel hub assembly. Lower the trailer onto the jack stand and leave the jack in place.

5

Finish loosening and removing the lug nuts from the rear wheels. Pull the wheels off and place them flat down. Begin the brake shoe replacement process of the driver side rear wheel hub.

6

Locate the round dust cap on the front of the brake drum. Tap the dust cap outward with a rubber mallet until it is free of the brake drum. Place the dust cap in a safe area.

7

Remove the cotter pin from the castle nut that holds the brake drum in place with the pliers. Bend the cotter pin straight and then pull it out of the center of the castle nut with the pliers. Loosen and unscrew the castle nut with a 1/2-inch drive ratchet, extension and a 1/2-inch drive socket. Once the castle nut is out of the way, shake the brake drum back and forth with your hands to loosen the roller bearing inside of the brake drum. Pull the bearing out along with the flat washer that is behind the roller bearing. Place the parts in a safe area.

8

Pull the brake drum straight off with your hands. If the drum is stuck, use the rubber mallet to tap the back side of the drum until it is loose enough to remove from the brake shoes. Pull the drum off and set it to the side.

9

Remove the two upper return springs that are located at the op of the backing plate with a spring removal tool. Also remove the washer that is behind the return springs. Loosen the brake spring retainer clips from each brake shoe with a brake spring retainer removal tool. Pull the retainer clip, retainer spring and the retainer out of the brake shoes and place them in a safe area.

10

Pull the top of the outer brake shoe off of the brake adjuster that is located on the bottom of the backing plate. Remove the brake adjuster and the spanner spring from the backing plate with your hands. Grab the brake shoes at the top and pivot the shoes away from the wheel cylinder and off of the backing plate.

11

Transfer all of the new braking accessories that come with the new brake shoe kit to the new brake shoes. This includes the retainer springs, retainers and the retainer clips. Position the new brake shoes with new braking accessories onto the backing plate. Position the brake adjuster and the spanner spring back onto the bottom of the backing plate. Pull out on the bottom of the brake shoes and position the bottom of the brake shoes onto the brake adjuster. Rehook the spanner spring with your hand.

12

Slide the washer back over the top return spring anchor. Rehook the two upper return springs to the anchor and to each brake shoe. Make sure that all of the new braking accessories are properly attached to the brake shoes and the backing plate. Move to the rear passenger side of the boat trailer and repeat the same process as outlined in the steps above to replace the drum brakes. Inspect the brake drums for any damage such as cracking or breaking.

13

Slide the drums over the new brake shoes. If the drums will not fit over the new brake shoes, remove the rubber plug on the lower back side of the backing plate with a flat-head screwdriver. Slide a flat-head screwdriver into the access hole and locate the star brake adjuster gears. Turn the star brake adjuster gears counterclockwise with the flat-head screwdriver until the brake shoes have retracted low enough to slide the drum on. Slide the brake drum over the new brake shoes and readjust the brake shoes so that the shoes are about 1/8 inch away from the inside of the drums.

14

Reinsert the flat washer, roller bearing and the castle nut onto the spindle inside of the brake drum. Screw the castle nut on tight with your hands. Completely tighten the castle nut with the ratchet and socket. Push the cotter pin back through the center of the castle nut and bend the cotter pin with the pliers so that it does not come out of the nut and so that the nut does not back off of the spindle. Position the dust cap back onto the middle of the drum. Tap the dust cap into position with the rubber mallet.

15

Slide both rear wheels onto the wheel hubs and screw the lug nuts on tight. Jack both sides of the boat trailer up and remove the jack stands. Lower the boat trailer to the surface and finish tightening the lug nuts with the tire tool until the lug nuts are very tight.