How to Replace Trailer Drum Brakes

The drum brakes on a trailer's wheels use brake shoes that are installed much like the brake shoes on most cars and trucks. The shoes drag against the brake drum when applied to halt movement. Replacing these brakes involve disconnecting the full assembly of shoes and springs that work together. You also should replace the springs, as they can wear down from the heat. A full replacement brake shoe set should include replacement springs.

Instructions

Removal

1

Raise the trailer with a floor jack and support it on jack stands. Remove the wheels on both sides of the trailer.

2

Pop the grease cap off the hub using a mallet and a large flat screwdriver as a wedge. Pull the cotter pin out of the hub with pliers, then loosen the drum's castle nut with a socket or ratchet wrench and remove the drum.

3

Disconnect the two upper return springs using a spring removal tool on the central pin, removing the pin and the washer beneath it.

4

Remove the hold-down spring for the rear brake shoe and then pull out this shoe slightly to remove the adjuster wheel at the bottom.

5

Unscrew and remove the front shoe's hold-down spring and remove the front shoe, then remove the rear shoe.

6

Twist the disconnected adjuster screw until it is completely closed.

7

Clean and wipe off the backing place with a rag.

Installation

8

Install the replacement front shoe on the backing plate, using the top retaining pin to pivot it into position and engaging it with the push rod near the middle, and fasten its own retaining pin and spring.

9

Connect the rear shoe to the front one using the replacement lower spanner spring and then reconnect the star adjuster screw to the plate and shoes, making sure the star wheel points toward the trailer's rear end.

10

Connect the rear shoe to the upper pin and then install the shoe's keeper pin and the first replacement return spring. Install the large flat washer and the second return spring with your spring installment tool.

11

Pull out the plug in the back of the plate and turn the star wheel with a screwdriver until the shoes barely avoid touching the outside of the drum assembly.

12

Place the drum back on the assembly and tighten the castle nut. Tighten it to about 35 foot-pounds while turning the drum forward to seat the bearings, then loosen the nut to finger tight and install a new cotter pin.

13

Reinstall the dust cap, tapping it with a hammer and wood block.

14

Reconnect the wheels after changing both brakes.

15

Adjust the star wheel with your screwdriver while turning the brake drum until the drum drags, then turn the wheel the other way until it just stops dragging.

16

Lower the trailer off the jack stands.