Tutorial: How to Change Brake Pads?

[bendix]

Changing Brake pads should only be carried out by a qualified mechanic. This thread is to outline and help you understand the process.

Why change your brake pads?

Safety is the most important thing when driving. If your brake pads are worn, chipped or burnished then the braking system may not be working as efficiently as it should. Brake pads should be inspected regularly and changed to suit your driving style/driving conditions. Bendix offers brake pads to suit all driving styles and conditions. The best sign of worn brake pads is pad thickness but another good indication that pads may need changing is noise, especially if they begin to make a persistent metallic squeaking or grinding noise when you press the brake pedal.



Please note: It is important to have your rotors "machined" by a brake service shopevery pad change or replaced if they are too thin.



But how do you change brake pads? It normally takes no more than an hour. Please note: This guide is for a “slide caliper” type braking system. Your car may have drums or a “fixed caliper” system.


Important: Change your brake pads one side at a time.


There are two main reasons for this.

1. When changing the front pads you can turn the steering wheel so that the calipers are facing out, giving you more room to work.
2. You will need to push back the caliper pistons the effects of this will be explained later in the guide.
3. Doing them one side at a time also means you have an assembled brake for reference in case you can't remember how things go back together.


Time to change your pads

1. Crack the wheel nuts whilst the car is on the ground still, it is much harder to crack them when the wheel is in the air as it has no resistance. Once the wheel nuts are cracked you can jack the car up. Use a jack stand to support the car as jacks can fail. You can now remove the wheel nuts and the wheels. You should now have access to the brake caliper.



2. Find the slider bolts/pins. They will be on the caliper side facing the middle of the car. Loosen the top bolt and remove the bottom slider bolt. This will allow the caliper to flip up, the reason we flip the caliper up and not down is so that the brakes lines can stay attached. They will flex but don’t worry; they are designed to do so.



3. At this point you will be able to see how worn the pads are. Remove the exposed pads and shims (if your car uses shims). The pads should be held loosely in using retaining clips but with little encouragement the pads will come out leaving the retaining clip in place.



4. A comparison between a worn and a new brakepad. From this comparison it is easy to see the difference in pad thickness.
5. The new pads can then be slid into the retaining clips, exactly as the old ones were.



6. Now to elaborate on why we only change brake pads on one side at a time. When you press the brake pedal the brake fluid forces these pistons to protract which pushes the pads against the brake rotor. The pistons will need to be pushed back to accommodate your new thicker Bendix Pads. Depending on the type of caliper you have a piston retraction tool may be used to screw or push the pistons back into the caliper. By doing this, the brake fluid in the pistons is being pushed back into the master cylinder reservoir through tiny passages, so the pistons move slowly. This puts pressure on the other pistons which, if had no resistance (brake pads left in), would fully extend and make life difficult. Make sure you push all the pistons in the same caliper back evenly. If you pushed in one by itself, the other would pop out — you don't want that. This is where having single piston brakes can be beneficial. Take care and be patient to ensure you don't nick or tear the rubber boot and seal that encircles the pistons.



7. When pushing the piston back, it's best to crack the bleed screw and get rid of the fluid that has been in the caliper. Fluid in the caliper can be heat affected or contaminated by debris - forcing this back through the ABS valve is not good for the ABS system. If the bleed screw is cracked, the hydraulics system has been opened and the system will require bleeding. Brake fluid should be flushed through and replaced every 2 years. Very few cars get new pads every 2 years, and even fewer get a fluid change between pad changes, so it's 99.9% certain that a car getting new pads also needs new Bendix brake fluid.



8. Pushing back the pistons will force brake fluid into the master cylinders reservoir. It should not overflow but just check it. Another reason to change brake pads one corner at a time.
9. When the pistons are fully retracted you may flip down the caliper and retighten the slider bolts. The caliper will be tight, if the piston catches the pads re-check that the piston is all the way in.
10. Repeat steps for each corner. Check the fluid levels and top up, take away or change if needed but be careful as brake fluid is extremely corrosive and will eat through car paint. Bleed the brakes if you have a spongy feeling brake pedal. Take the car for a test drive to make sure everything is working correctly. Be careful during the first few stops to get use to the new pads. The brakes will engage at a higher pedal point than before as the pads are thicker. Thank you for choosing Bendix and drive safely.

Special Note: Bendix and the forums recommend brake pads and any mechanical work to be done by a qualified mechanic. Bendix and forum do not take any responsibility for damages to your vehicle or well-being. Care should be taken at all times.

For more information on Bendix Brakes, visit: www.bendix.com.au