The short version
- The brake is the obstacle, not the bearing. Getting the drum off is most of the job.
- A drum that will not move is usually held by shoe wear ridge or rust, and both have a fix.
- Back the adjuster off before pulling, through the slot at the back or through the drum.
- Readjust the shoes afterward, or the pedal will be low and the parking brake weak.
A rear wheel bearing drum brakes job is the same bearing job with a brake job wrapped around it. The bearing itself rarely causes trouble.
What causes trouble is a drum that has not come off since the car was built.
A disc rear with a drum in the hat is different again. Which layout you have
On many designs the bearing lives inside the drum itself, so removing the drum removes the bearing with it.
On others the drum slides off a separate hub, and the bearing stays behind on the spindle or in the hub flange.
A dust cap and castle nut in the middle of the drum means tapered bearings inside it. A plain drum with no center hardware means the bearing is elsewhere.
Working out which axle layout you have is on the rear procedure page.
Getting the drum off
This is where a wheel bearing job behind drum brakes actually goes wrong.
Three obstacles, and they are cumulative.
The wear ridge. The shoes wear a groove into the drum. That leaves a lip at the open edge which catches as the drum comes off.
Rust at the center. The drum seizes on the hub pilot in exactly the way a rotor does.
The parking brake. A cable that has adjusted itself tight holds the shoes out against the drum.
There is a slot at the back of the backing plate, or sometimes on the drum face, with a rubber plug in it.
Reach in with a screwdriver or a brake spoon and wind the star wheel back. That removes the wear ridge problem entirely.
When it still will not come
- Release the parking brake fully and check the cable is not holding tension.
- Back the adjuster right off, further than feels necessary.
- Penetrant at the center, then wait rather than pulling.
- Use the threaded holes if the drum has them, with two bolts wound in evenly.
- Strike the drum face between the studs, alternating positions, never on the edge.
The backing plate is thin pressed steel and bends easily, and a bent one rubs the drum forever afterward.
The same applies to hitting the drum rim, which cracks cast iron more readily than people expect.
The rear wheel bearing drum brakes job itself
Once the drum is off, this is an ordinary bearing job of whichever type you have. Nothing about drum brakes changes it from here.
Tapered bearings inside the drum come out, get cleaned and packed, and go back with a new seal and a fresh adjustment.
A bolt on hub behind the drum unbolts from the backing plate side.
A pressed in bearing follows the usual pressing rules.
Those procedures are on the repacking guide and the pressed in procedure page.
The part specific to drum brakes
The inner seal is the only thing between packed grease and the friction material a few inches away.
Fit a new seal without exception, and wipe the inside of the drum before it goes back on.
What happens when grease reaches the shoes is on the escaping grease page.
Putting it back and adjusting
The step people skip, and it shows up immediately.
Shoes backed off for removal have to be wound back out. Turn the star wheel until the drum drags slightly, then back off until it turns freely.
Do it on both sides equally. Uneven adjustment gives a pull under braking, and it gets blamed on everything else.
Shoe adjustment and parking brake travel are linked, so a drum job usually needs the cable checked too.
A parking brake that now needs far more travel is a sign the shoes are still under adjusted.
Common questions
How do you do a rear wheel bearing drum brakes job?
Back off the shoe adjuster, remove the drum, then do the bearing job for whichever design is behind it, and readjust the shoes.
Why will my drum not come off?
Usually the shoe wear ridge catching, rust seizing it on the hub center, or a parking brake cable holding tension.
Where is the adjuster?
Behind a rubber plug in a slot in the backing plate, or occasionally through a slot in the drum face itself.
Can I hit the drum?
On the flat face between the studs, alternating positions. Never on the rim, and never lever against the backing plate.
Where do rear wheel bearing drum brakes bearings sit?
Sometimes. A dust cap and castle nut in the center means tapered bearings inside it. A plain drum means the bearing is behind it.
Do I have to readjust the shoes?
Yes. Backed off shoes leave a low pedal and a weak parking brake until they are wound back out evenly on both sides.
Do I need a new seal?
Always. The seal is the only thing keeping grease off the brake shoes a few inches away.