Drum brakes lose stopping power when the friction material wears down, and adjustment brings the brake shoes closer to the drum so they engage sooner

Drum brakes work by pushing curved friction pads (called shoes) outward against the inside of a rotating drum. Over time, the friction material wears thin, and the shoes sit farther from the drum than they should. Adjusting drum brakes means moving the shoes closer to the drum so they grab at the right point in the pedal travel. This is different from replacing the shoes — adjustment is a temporary fix that buys you time before the friction material gets too thin to be safe.

Most drum brakes adjust themselves slightly as you drive, but if your brake pedal feels soft, sinks toward the floor, or requires harder pressure than usual, manual adjustment is usually needed. You can do this yourself with basic hand tools in about 30 minutes per wheel, though the exact steps depend on whether your drums have an adjustment slot on the back or require the drum to be removed.

Key Takeaways

  • Drum brake adjustment moves the brake shoes closer to the drum to restore stopping power when the pedal feels soft or sinks.
  • Some drums have a slot on the back that lets you adjust without removing the drum; others require you to take the drum off and adjust from inside.
  • You will need a brake spoon (a long tool with a notch at each end) or a screwdriver, a flashlight, and jack stands to safely lift the vehicle.
  • Adjustment should be done evenly on both wheels of the same axle so the brakes pull straight and do not cause the vehicle to veer.
  • If the pedal still feels soft after adjustment, or if friction material is visibly worn away, the shoes need replacement, not just adjustment.

What you need before you start

Gather your tools and materials in one place so you do not have to hunt for them mid-job. You will need a brake spoon (a specialized tool with a notch at each end, sold at any auto parts store for under $15) or a large flathead screwdriver, a flashlight or work light, a jack and jack stands rated for your vehicle's weight, and wheel chocks (blocks or wedges to keep the vehicle from rolling). Wear safety glasses because brake dust can fly into your eyes, and wear gloves because brake dust contains asbestos in older vehicles and is toxic to inhale.

Park on level ground, set the parking brake, and chock the wheels that will stay on the ground. Loosen the lug nuts on the wheel you are working on before you jack up the vehicle — it is much easier to break them loose when the wheel is on the ground and the vehicle's weight holds it still. Then jack up the vehicle, remove the wheel, and set the vehicle on jack stands. Never work under a vehicle supported only by a jack.

Adjusting drums with a slot on the back

Some drum brakes have a small rectangular slot on the back of the drum, usually covered by a rubber or plastic plug. This slot lets you adjust the shoes without removing the drum. Peel back or remove the plug and shine your flashlight into the slot so you can see the adjuster wheel inside — it looks like a small gear with a notch on one side.

Insert the brake spoon or screwdriver into the slot and hook the notch of the adjuster wheel. Rotate the wheel toward the front of the vehicle (the direction depends on which side of the vehicle you are on, so test gently first). Each click of the adjuster tightens the shoes slightly. Spin the drum by hand after every few clicks — it should turn freely but with noticeable resistance, like a wheel with old bearings. Stop when the drum is hard to turn but not completely locked. Back off the adjuster by one or two clicks so the drum spins freely again with just a little drag.

Repeat this process on the other wheel of the same axle (both rear wheels, or both front wheels if your vehicle has front drum brakes, which is rare). Uneven adjustment causes the vehicle to pull to one side when you brake. Reinstall the rubber plug, put the wheel back on, and tighten the lug nuts in a star pattern (opposite sides alternately) so the wheel sits evenly.

Adjusting drums that require removal

If there is no slot on the back of the drum, you will need to remove the drum to access the adjuster. The drum is held on by the lug nuts and sometimes by a small clip or screw. Once the lug nuts are off, pull the drum straight toward you. It may be stuck; tap the back gently with a rubber mallet or rock it side to side while pulling. Do not hit the friction surface (the inside) or you will damage it.

With the drum off, you will see the brake shoes and the adjuster mechanism. The adjuster is usually a small screw or gear at the bottom of the shoe assembly. Use the brake spoon to rotate it — the direction depends on the design, so look for an arrow stamped on the adjuster or test gently. Rotate in small increments and check your progress by reinstalling the drum and spinning it by hand. The drum should turn with resistance but not lock up. Once the adjustment feels right, reinstall the drum and lug nuts.

Testing your adjustment and knowing when to stop

After adjusting both wheels on the same axle, reinstall the wheels, lower the vehicle, and tighten the lug nuts fully in a star pattern. Before driving, pump the brake pedal several times while the vehicle is parked. The pedal should feel firm and should not sink toward the floor. Take the vehicle to an empty parking lot or quiet street and test the brakes at low speed, then at higher speed. The vehicle should stop straight without pulling to one side.

If the pedal still feels soft or sinks, the friction material may be too thin to adjust. Measure the thickness of the brake shoes by looking at them through the slot or after removing the drum — most shoes should be at least 1/8 inch thick. If they are thinner than that, or if you can see bare metal underneath the friction material, the shoes need replacement, not adjustment. Continuing to drive on worn shoes risks brake failure.

Why adjustment is temporary and what comes next

Brake shoe adjustment is a short-term fix because it does not replace the worn friction material — it only moves the shoes closer to the drum. As you continue to drive, the shoes wear down again and the pedal will gradually feel softer. How long adjustment lasts depends on your driving habits and how much material was left when you adjusted. Some people get months of good braking; others get only weeks.

When the pedal starts to feel soft again, you have two choices: adjust again, or replace the shoes. Most mechanics recommend replacing the shoes once they reach 1/8 inch thickness, because thinner shoes overheat more easily and can fail suddenly. Replacement is more expensive than adjustment but lasts much longer — typically 30,000 to 50,000 miles depending on driving conditions.

Common mistakes that make brakes worse

The most common mistake is adjusting only one wheel instead of both on the same axle. This causes the brakes to pull hard to the side that is tighter, making the vehicle difficult to steer during braking. Always adjust both rear wheels or both front wheels together, and test the adjustment by braking in a straight line in an empty lot.

Another mistake is adjusting too tight. If the drum is hard to spin or locks up, you have tightened too much. Back off the adjuster by one or two clicks so the drum spins freely with just a little drag. Brakes that are too tight overheat, fade during hard braking, and wear out faster. A third mistake is adjusting when the friction material is already too thin. If the shoes are visibly worn down to bare metal, adjustment will not help — the shoes need replacement.

Frequently Asked Questions

How often should I adjust my drum brakes?

Adjust only when the brake pedal feels soft, sinks toward the floor, or requires noticeably harder pressure than usual. Do not adjust on a schedule. Most vehicles go months or years between adjustments, depending on driving habits and how much friction material is left on the shoes.

Can I adjust drum brakes while the vehicle is on a jack without jack stands?

No. A jack can fail or slip, and if it does, the vehicle will fall on you. Always use jack stands rated for your vehicle's weight, and never work under a vehicle supported only by a jack. This is a safety rule, not a suggestion.

What if the adjuster wheel will not turn?

The adjuster may be rusted or stuck. Spray it with penetrating oil (like WD-40) and wait 15 minutes, then try again. If it still will not budge, do not force it — you risk breaking the adjuster. In this case, the shoes likely need replacement anyway, so have a mechanic inspect them.

Do I need to bleed the brakes after adjusting?

No. Drum brake adjustment does not involve the hydraulic system, so bleeding is not necessary. Bleeding is only needed if you have opened a brake line or replaced hydraulic components like the master cylinder or wheel cylinder.

Why does my brake pedal feel soft again just days after I adjusted?

If the pedal sinks quickly after adjustment, the problem may not be shoe wear — it could be a leak in the hydraulic system, air in the brake lines, or a failing wheel cylinder. Have the brakes inspected by a mechanic to rule out these issues before adjusting again.