Changing brake pads on a motorcycle
Changing your brake pads is not difficult in principle; however, great care must be taken when doing so. You must therefore read these instructions very carefully.
Changing brake pads – step-by-step instructions
Both brake pad and brake disc are subject to frictional wear and tear, the degree of which will depend on your riding style and braking habits. So regular visual checks on the state of the brake pads are essential for your own safety. They can usually be inspected by lifting a cover on the brake caliper. You will now be able to see the brake pads: they consist of a friction lining which is adhesively bonded to a base plate. The lining often has a coloured marking to indicate the service limit of the brake pads, which is usually a thickness of 2 mm. Please also inspect the brake pad from the side and from underneath. Uneven wear indicates incorrect mounting of the caliper, and can cause premature damage to the brake disc! If you're planning a long tour, it's always wise to replace the brake pads, even if they still seem to have some wear left before they reach the service limit. Older brake pads, or ones that have frequently run hot, can also become less effective due to vitrification of the material they are made of. In this case, they should be replaced. You should also check the brake disc every now and then. Modern lightweight brake discs, especially, are subject to considerable wear and tear from the "bite" of the four- or six-piston brake caliper. You can measure the residual thickness of the disc using a micrometer.
Important: Over time, a ridge will form on the outer edge of the disc, which is itself indicative of considerable wear. However, if you measure the disc using a caliper gauge, this ridge can falsify the reading! Compare your measurement with the service limit, which is generally stamped on the base of the disc, or look it up in the workshop manual. Make sure that you always replace the disc in good time. Allowing the disc to fall below the minimum allowed thickness may result in brake fade and simultaneous overheating in the system, as well as irreparable damage to the brake caliper! Also replace the disc if it is deeply scored.
Remove brake caliper
First of all, cover up the tank and any other paintwork near the brake fluid reservoir.This is to prevent brake fluid overflowing and damaging the paintwork when you retract the brake piston. Brake fluid leakage can make a mess of your paintwork, so it must be washed off immediately with plenty of water (not just wiped off with a cloth). Jack the motorcycle up so that the fluid reservoir is positioned horizontally and the fluid does not run out as soon as it is opened. Now open the cap, remove it with a cloth, and suction out roughly half of the fluid from the reservoir. If the fluid has been in the reservoir for more than two years, it's best to change it completely; you will be able to see it's due for replacement by the brownish colour (see DIY tip "Brake hoses")!
The most professional way to draw out the fluid is to use a Mityvac brake bleeder or a pump bottle.
Release the brake caliper mounting from the fork and lift the caliper off the disc so that you can get to the brake pads. Use a disc brake piston spreader to push back the movable brake pad or pads into its/their retracted position uniformly and without tilting in order to create space for the new thicker pads. If you do not have a disc brake piston spreader, you can also use two screwdrivers – although this increases the risk of tilting, which makes the brake piston stick slightly and would result in brake drag. Also keep an eye on the brake fluid in the reservoir when spreading the pistons, as the reverse movement of the piston causes the fluid level to rise!
Remove brake pads
The actual removal of the brake pads is very easy. Our illustration shows brake pads that are guided by two holding pins and held in place by a spring. Remove the securing clips from the pad retainers, and then take off the retainers. If the pins are jammed, drive them out with a suitable punch. Caution: The spring has a habit of jumping out and hiding in some dark corner of your workshop. It is important to make a note of the installation position so that you can can refit it correctly later. Once you have removed the pins, you can take out the brake pads. Bear in mind that your bike may be fitted with "anti-squeal plates", which are located between brake pad and piston. They must be correctly re-installed in the same position in order to do their job!
Clean and inspect brake caliper
Thoroughly clean and inspect the brake calipers. In particular, check that they are dry on the inside, and make sure the dust sleeves on the brake piston are installed correctly. Any moisture would indicate that the piston is not properly sealed. The dust sleeves must not be brittle or porous, as this would allow moisture to penetrate the piston. The dust sleeve is easy to replace externally, but you will need to refer to the repair manual for replacement of the seals. Use a soft brass wire brush or plastic brush and Procycle brake cleaner to clean the brake caliper as shown in the illustration. Avoid spraying the cleaner directly onto the dust sleeve. Do not brush the sleeve!
Install brake pads
Before fitting the new brake pads, apply a thin layer of Procycle copper paste to the metal rear surface and the edges. If your bike has ABS, use Procycle anti-squeal paste. Always make sure that no copper paste/anti-squeal paste comes into contact with the pad(s)! The paste prevents the brakes from squealing, and you should also apply a thin layer to the holding pin. Thoroughly clean the pins – or even better, replace them. Now place the pads in the caliper with the inner surfaces facing each other. If your brakes have anti-squeal plates, position them correctly. Insert one holding pin and place the spring on top. Press the spring down and insert the second holding pin. Attach new securing clips. Make sure you have done everything correctly before moving on to the final step of this job.
To position the brake caliper over the disc, you need to move the pads as far apart as possible in order to create enough space. Now place the caliper over the disc at the fork. If you are unable to do this, the brake piston has probably shifted slightly away from its retracted position and you will need to push it back. If possible, use two pieces of wood for this to avoid damaging the new brake pad. Once again, apply pressure evenly from both sides and be sure to avoid tilting! When the brake caliper is in position, tighten to the specified torque.
If your bike has a single-disc brake, you can now refill the brake fluid in the reservoir up to the "Max." mark and close the cap. If your bike has a dual disc brake system, you will first need to fit the second brake caliper. Before taking a test ride, "pump" the brake lever a few times in order to push the brake piston into the correct operating position. This is very important, as otherwise your first braking attempts would have no effect! Try to avoid constant and hard braking for roughly the first 150 miles so that your pads can bed in gently and don't vitrify. Check whether the discs run hot, the brake pads squeal or whether there are any other problems that may indicate that the brake piston is jamming. In this case, follow the steps described above to push the piston back into its retracted position while at the same time taking care not to tilt it. This will generally fix the problem.
You should only replace brake pads yourself, following the instructions below, if you are an experienced DIY mechanic. Don't put your safety at risk! So if you're not sure you're able to do the job, definitely leave it to the professionals!
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These tips for DIY mechanics contain general recommendations that may not apply to all vehicles or all individual components. As local conditions may vary considerably, we are unable to guarantee the correctness of information in these tips for DIY mechanics.
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