How to Rebuild Drum Brakes Step by Step
Drum brakes were standard equipment on every American car through the early 1970s, and they remained on rear axles well into the 1980s. If you are restoring a classic, there is a very good chance you are dealing with drums on at least one axle. The good news: drum brake rebuilds are straightforward, inexpensive, and deeply satisfying when you feel that firm pedal for the first time after the job is done.
This guide walks through a complete drum brake rebuild: disassembly, inspection, hardware replacement, shoe installation, and adjustment. We will assume you are working on a typical rear drum setup, but the process is nearly identical for front drums.
Before You Start: Safety and Parts
Order a complete hardware kit for both sides before you start. These kits include return springs, hold-down springs, adjusting hardware, and all the small clips and pins that fatigue over decades. Reusing 50-year-old springs is a false economy — a broken return spring can leave a shoe dragging against the drum, overheating the brake and potentially causing a fire.
Drum Brake Hardware Kit
Complete hardware kit with springs, pins, adjusters, and clips. Available for most American classics. Always replace hardware in pairs — both sides.
Step 1 — Remove the Drum
With the car safely on jack stands and the wheel removed, the drum should pull straight off the hub studs. If it is stuck (and it will be, after decades), try these approaches in order:
- Back off the adjuster: There is usually an oval slot in the backing plate. Insert a brake spoon or flat-blade screwdriver to turn the star wheel adjuster, retracting the shoes away from the drum.
- Penetrating oil: Spray the hub/drum interface and let it soak for 15 minutes.
- Heat: A propane torch on the drum center hat (not on the friction surface) can break the rust bond.
- Puller: Some drums have threaded holes in the face for bolts that jack the drum off the hub when tightened evenly.
Once the drum is off, set it aside and take a photo of the brake assembly before touching anything. This is your reassembly reference.
Step 2 — Disassemble One Side at a Time
Work on one side at a time so you can reference the assembled side if you get lost. Drum brakes have a lot of small springs and clips, and they all go in specific locations.
Remove the hold-down springs and pins (push in and twist 90 degrees), then unhook the return springs from the anchor pin at the top. Note which spring goes where — the primary (shorter) shoe and secondary (longer) shoe have different springs on some applications. Remove the self-adjuster assembly and the parking brake strut or lever. The shoes will now lift off the backing plate.
Step 3 — Inspect Components
Drums: Measure the inside diameter with a drum micrometer or a large caliper. Compare to the maximum diameter stamped on the outside of the drum. If the drum is within spec and the friction surface is smooth, it can be reused. Light scoring can be machined out on a brake lathe. Deep grooves, heat cracks (blue spots), or out-of-round drums beyond the wear limit get replaced.
Wheel cylinders: Inspect for leaks at the dust boots. Any weeping of brake fluid means the cylinder is shot. You can rebuild them with a hone and a seal kit, but new wheel cylinders are inexpensive and the safer option. Replacement is strongly recommended on any car that has been sitting for years.
Backing plate: Check the six shoe contact pads (raised platforms on the backing plate where the shoe web rides). If they are grooved or worn thin, the shoes will not slide smoothly during application and release. Light grooving can be cleaned up with a file. Heavily worn pads mean a new backing plate.
Wheel Cylinder Pair
New wheel cylinders eliminate the most common source of drum brake leaks. Available for most classic applications. Always replace in pairs.
Step 4 — Prepare the Backing Plate
Clean the backing plate with brake cleaner. Apply a thin film of high-temperature brake grease to the six shoe contact pads and the anchor pin. This allows the shoes to slide freely during braking. Do not get grease on the friction surface of the shoes or the drum.
Step 5 — Install New Shoes and Hardware
Place the new shoes on the backing plate with the primary shoe (shorter lining) toward the front of the car and the secondary shoe (longer lining) toward the rear. Install the hold-down pins and springs. Reconnect the self-adjuster mechanism — make sure the star wheel adjuster threads freely and the cable or lever engages correctly. Hook the return springs onto the anchor pin.
Install the new or rebuilt wheel cylinder if you removed it. Reconnect the brake line, but do not tighten the bleeder screw yet — you will need it open for bleeding.
Step 6 — Install the Drum and Adjust
Slide the drum back over the shoes. If the shoes are too wide (from a fully extended adjuster), retract the star wheel. The drum should spin freely with a very slight drag. Adjust the star wheel outward until you feel the shoes contact the drum, then back off two to three clicks until the drum spins freely again.
Repeat the entire process on the opposite side. Remember: the shoe layout is a mirror image, so primary and secondary positions are reversed left to right.
Step 7 — Bleed the Brakes
If you replaced wheel cylinders or opened any brake lines, you must bleed the system. Start at the wheel farthest from the master cylinder and work toward the closest. Use a clear tube on the bleeder screw and pump the pedal until no air bubbles appear in the fluid stream. Top off the master cylinder reservoir between each wheel.
After bleeding all four corners, pump the brake pedal several times to seat the shoes against the drums. The pedal should feel firm and consistent. A spongy pedal means air is still in the system — bleed again.
Brake Bleeder Kit
One-person brake bleeder with check valve and collection bottle. Makes solo bleeding quick and mess-free.
Break-In Procedure
New brake shoes need a break-in period (also called bedding) to transfer a thin layer of friction material onto the drum surface. Make 20 to 30 moderate stops from 30 mph, allowing a few seconds between each stop for cooling. Avoid hard stops or holding the brakes during the first 200 miles. After break-in, readjust the star wheel if needed — shoes wear rapidly during initial break-in and the pedal may go low.
Final Recommendation
A complete drum brake rebuild with new shoes, hardware, and wheel cylinders costs under a hundred dollars per axle in parts and takes a few hours per side. The improvement in stopping power and pedal feel over worn, neglected drums is dramatic. Always work in pairs, always replace the hardware, and always bleed the system thoroughly. Your classic deserves brakes that work as well as it looks.