Brake Drum Bonding and Skimming: How to Keep Your Brake Drums in Tip Top Condition
As a responsible car owner, we should check our drum brakes at least every six months, 10,000 km, or as recommended in the car’s normal service schedule. During your service or check-up, your mechanic will be looking for worn brake linings.
Some older vehicles are fitted with a plugged inspection hole in the back plate, while other cars require the drum to be removed.
When inspecting the brake drums, your mechanic will take care to look for the tell-tale signs of wear and tear, as well as any more, serious threats that may cause underlying issues in your braking system.
Brake drums are very different when compared to brake discs; they require bit less maintenance, but are somewhat of an out-dated technology. Just as is the case with brakes discs, there is often a cheaper and easier way to boost their efficiency without t the need to replace them – which is known as brake re-bonding.
Should there be a need for your brake drums to be re-bonded, the mechanic will remove the entire brake drum and get to work, performing some of the below outlined checks and replacements:
- Linings may be riveted or bonded to the brake shoes. With riveted linings, replace the shoes well before the lining wears down to the level of the rivet heads. Exposed heads score and ruin the brake drums.
- Shoes with bonded lining should, for safety, be replaced when the lining is worn to & 1/10 in. (3 mm) thick, even if a minimum thickness of 1/16 in. (1.5 mm) is quoted in the car handbook.
- Always renew brake shoes on both wheels on an axle, even if the lining on one wheel is less worn than on the other. Renew on both wheels also if one lining has been fouled by oil or brake fluid. Otherwise, braking will be unbalanced.
- Buy only brake shoes that have a well-known maker’s name clearly marked and correctly spelled on the box. Dangerous fakes are common they often have names only slightly altered from a well-known make.
- If you have to get under the car, to look through the inspection hole in the back-plate, for example, raise the car and support it on axle stands, not just on jacks.
- Vital details include which way round brake shoes fit; the holes into which springs fit (there may be several similar-looking holes near the correct one); which way round springs go (the ends are often not the same length); the position of retaining pins and automatic adjustment parts; and the order in which washers are fitted.
- If the brakes are adjusted manually, slacken before you remove the drums. With self-adjusting brakes, slackening is usually neither necessary nor possible.
h/t to howacarworks.com for the information sourced for this article!
Re-bonding brake drums requires a lot of training and experience; it is not recommended you carry this out yourself.
Related Tags: Brake Disc Skimming
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Cover Image Credit: Pilgim Engineering