It’s hard to think of a more obvious safety item on your bike than the brakes. Faulty, worn or damaged stoppers can be deadly – and they’re often the source of MOT test failures too.
Luckily, it’s easy to keep an eye on the basics, and some quick daily checks on the main components of the brake system will help prevent any mishaps.
In this quick video, our tame bike journalists – Alan Dowds and Rob Hoyles – go through the basics of brake maintenance, with daily checks and more in-depth examinations at service time.
The guys show you how to check the levels and quality of your brake fluid, find any fluid leaks, and spot damaged brake hoses. They also take us through the main checks on brake pads, spotting excess wear and other problems, plus how to make sure your brake discs are within the manufacturer’s thickness tolerances.
Daily brake checks
Daily checks are easy to carry out on your brakes – and considering the potential for disaster, it’s worth getting into the habit. Start with the fluid – almost all bikes use hydraulic brake fluid to operate the brakes, and you need to check the level is correct, and also that the fluid is in good condition. As fluid gets older, it absorbs water, and that causes it to change colour from a very light yellow colour to a darker yellow, orange or even brown.
Checking the level is easy – just look at the fluid against the marks on the brake reservoir. There are two types – some reservoirs have a solid metal construction, and use a small sight glass with a level mark, others use a translucent plastic body, with the level marked on there. Whichever type, make sure the fluid is above the ‘minimum’ level, and below the ‘maximum’ if there is one.
If the fluid is low, then top up with the recommended type, and if it’s very dark in colour, consider changing the fluid – which will probably mean a trip to the garage if you’re not reasonably comfortable with the spanners.
After checking the fluid, take a look at the hoses which run from the handlebars to the calipers. You’re looking for leaks or damage here, and any of that is very bad. If there’s any brake fluid at all leaking or visible damage to rubber hoses, that needs professional help sharpish.
Brake pads and discs
Finally, you want to look at the wear levels on the brake pads and discs. Starting with the discs, you’re looking for any serious grooves, cracking or excess wear. The discs will usually have a ‘minimum thickness’ marking on them, and you need to use a dial gauge or micrometer device to check the thickness of the disc. Bear in mind that the very outer edge of the disc is usually not worn down by the brake pads, so you need to measure the thickness on the inner part of the disc, where the pads ‘bite’.
Pads can be visually inspected on almost all caliper designs, usually by looking in from the back of the caliper or in at either end. Most pads have wear marks in them – a groove down the middle of the pad that shows the recommended minimum thickness, usually a couple of millimetres. But if your pads are getting close to the minimum, it’s worth changing them a bit early – the performance will be declining, and you’re not making a big saving by hanging on to the last minute. Thinner pads transfer more heat to the brake caliper and fluid, reducing efficiency, and if they start to wear down to the metal, you risk damaging the discs and making the job much more expensive.