SERVICING HANDBRAKE DRUMS
You should routinely strip, inspect and clean the handbrake shoes inside a brake drum. Start by making sure the handbrake is off and its cables are slack. You may need to back-off the adjustment on the handbrake cable to ensure it’s slack.
Some drum brakes have automatic adjustment (ie, a ratchet system), so the only way to remove the drum is to ensure the handbrake cable is slack. Hitting the face of the drum with a hammer can help to shock and release the brake shoes, which should make it easier to prise off the drum by hand.
If the brake shoes inside a drum can be adjusted, look for an access hole to back-off these adjusters. Some cars have one or more access holes in the backplate. Use a screwdriver to turn the adjusters and back-off the brake shoes.
If the brake shoes can be adjusted manually, wind the adjuster to check it hasn’t seized. Spray it with a light grease, then wind it in and out using pliers or a flat-blade screwdriver. This will help prevent it seizing in the future and make it easier to adjust.
Some rear brake drums have an access hole in the face of the drum brake, which has to be positioned at the top to access the adjuster and back it off with a screwdriver. Shine a torch through the access hole to find the adjuster. Spraying a little penetrating fluid inside will help the adjuster move.
Once the drum has been removed, spray the brake shoes and mechanism with brake cleaner to dampen any dust, then use a wire brush to clean around the backplate where dirt collects.
Use a flat-blade screwdriver to scrape off any dirt collected against the edges of the braking material on the shoes, which could lessen the performance of the handbrake. Check the condition of the braking material to see if it’s damaged or worn.
The brake shoes can drag against the backplate, so carefully prise them away with a screwdriver, then apply copper grease where they make contact. Do not apply grease to the braking material of the shoes.
Locate the handbrake mechanism and make sure it moves freely. Spray over any moving parts with a light grease and operate the mechanism to make sure it hasn’t seized. If the handbrake works on a ratchet system, operating it may push the shoes out, so the mechanism will need to be released or retracted before refitting the drum.
After cleaning and lubricating the brake shoes and handbrake mechanism, the brake shoes may be slightly misaligned, so use a couple of screwdrivers to adjust the positioning of the brake shoes to ensure there’s an even gap between them and the backplate all the way around.
As mentioned in Step 2, before attempting to remove a drum, hit the face of the drum with a hammer to release it. This helps to move the brake shoes inside, which may have seized. Don’t hit the edges of the drum as it could warp it, in which case it should be replaced.
Inspect the condition of the inside of the brake drum and renew it if it’s heavily scored. If there’s a lip around the outer edge, this will make the drum difficult to fit and detach, so try to remove it with an angle grinder and grinding disc. Refit the drum, then see Handbrake adjustment.