How to Replace Disc Brakes

Buy Brake Discs At FCP Groton Steps

1. Determine what parts and tools you'll need. If the front brakes are squealing loudly, you'll need pads only. If the car shakes when braking, you'll need to have the rotors resurfaced (called "turning"), or replace them. If the car pulls to one side while braking, but stays straight otherwise, you may need calipers.
2. Go to the parts store and buy more parts than you think you'll need. You can always return what you don't use, and if you get caught without something while the car is apart, you may not be able to go anywhere to buy anything.
3. Park the car in a clean, well-lit place. Block the rear wheels with something heavy to prevent the car from rolling while it's jacked up. Apply the emergency brake (emergency brakes only use the rear, not the front). Give the car a good couple of shoves from side to side; if it's going to shift on the jackstands or fall off, better now than when you're partially under it with the wheels off.
4. Remove the front hubcaps and loosen the lug nuts before jacking the car up. If you skip this step, loosening the lugs may be very annoying, if not impossible. It is also extremely dangerous to loosen lug nuts after a car has been jacked up.
5. Jack the car up with a floor jack and put it on jackstands. Make sure the jackstands are positioned under a solid part of the car - frame or subframe. Finish removing the wheels. Place the wheels under the car, just to the rear of the jackstands. In case the car slips off the stands, those wheels can prevent you from being caught under a falling car.
6. Make sure you have all the necessary tools. There are two bolts that hold the caliper to the pad bracket, and two bolts that hold the pad bracket to the steering knuckle. If you don't have the tools to remove these, now is the time to put the wheels back on and go to the hardware store. [You may need both SAE and Metric sizes of wrenches and sockets, as well as bleeder screw wrenches. Also, you may need a set of hex key wrenches or a hex bit socket set.]
7. Remove the caliper from the pad bracket. The pads may come out with the caliper, or stay in the bracket, depending on the car. Place the caliper on top of the steering knuckle, or hang it with a piece of clothes hanger wire or any other place where it won't be hanging from the brake hose.
8. Remove the pads and inspect them for wear. You may need to employ the large flat screwdriver to get the pads out. If either is down to the metal backing, you'll need to cut or replace the rotors. This is also a good time to compare the wear pattern of the left side brakes to the right side. If there is a vast difference, you'll need to replace the calipers.
9. Apply antisqueal paste to the backing of the new brake pads, but do not install them yet.
10. Inspect the brake rotors. If there are any grooves, or excessive glazing, remove them for resurfacing (called "turning") or replacement. Inspect the brake hoses. If they are leaking by the fittings or damaged, they'll need replacing - but that is outside the scope of this article. If you are only installing brake pads, skip to step 20.
11. Remove brake rotors. Unbolt the pad bracket from the steering knuckle. The bolts that hold this on tend to get frozen, so you may need to employ a hammer, breaker bar, Liquid Wrench or a torch to loosen them.
12. On most cars, the rotor is separate from the hub. Simply slide the rotor off of the studs. You may need to remove a set screw and/or use a rubber mallet to loosen the rotor. You may need an impact driver to remove a set screw. If the brake rotor and hub are one piece, remove the cotter pin and castle nut from the axle to allow removal.
13. To get the rotors resurfaced ("turned"), take them to a machine shop/auto parts store that turns rotors. Some auto parts stores have brake lathes or a machine shop. Call before starting your job to verify hours; most machine shops are only open until noon on Saturday and are closed on Sunday. Rotor/hub assemblies can be resurfaced ("turned"), but I would recommend just replacing them. Even though the replacement parts are expensive, you're replacing the hub and its bearings instead of putting the old hub and bearings back on the car. However, not all new rotor/hub assemblies include the bearings [although they usually install new races, so you can just "drop in" the new grease-packed bearings]. You may have to install them yourself, as well as pack them with grease. So a set of bearings may be a necessary purchase as well. [When applicable, this is also a good time to repack your front wheel bearings. Refer to your service manual or lubrication guide for this procedure. You'll need some new cotter pins and wheel bearing grease for this, as well as a pair of needle-nose pliers.]
14. Install the new or resurfaced ("turned") rotors the same way they came off. New rotors have a layer of oil on them to prevent rust while they're on the shelf. Clean this off with carb cleaner; it works better than brake cleaner in this case. Reattach the pad bracket. If you are not replacing calipers, skip to step 20.
15. Replacing calipers. Make sure the brake fluid reservoir is securely closed. Remove the bolt holding the brake hose to the caliper. This is a special hollow bolt that allows fluid to flow through it; don't lose it.
16. Drain the fluid from the caliper into a safe container for proper disposal.
17. The new caliper will come with two brass washers, rubber grommets for the slide pins, pad retaining clips (if applicable), possibly new slide pins, and maybe that hollow bolt mentioned above. Make sure that the calipers are installed with the bleeder fittings/screws in the upper or top position. If you accidentally switch the left and right calipers and install them on the wrong side (easier to do than you think!), the bleeder fittings will be in a lower position, which will result in trapped air inside the caliper fluid chamber, which will make bleeding the brakes impossible to do. Remember, bleeder screws UP!
18. If you need to reuse the old slide pins, clean them with a wire wheel or brush.
19. Reattach the brake hose by putting a new brass or copper washer on each side of the hose fitting, and the hollow bolt through. Reuse of the old washers, or failure to put the new ones in the right place will cause the brakes to leak. Tighten the bolt firmly.
20. If you haven't done so yet, clean the caliper slide pins, and any place where the pads slide against the caliper or pad bracket with a wire brush. Apply brake lubricant to all of those locations.
21. Compress the caliper piston, if necessary. Take one of the old brake pads and place it in the caliper against the piston. Using the large C-clamp (usually an 8" to 10" size {inner measurement} will do), slowly and evenly compress the piston back into the caliper. An even easier way to compress this piston is use a special (but inexpensive and readily available) Lisle Corp Brake Pad Spreader tool (Lisle part #24400 $7.95) made specifically for this--it beats hauling a heavy 10" iron C-clamp around--plus it's much faster to use! Some brake fluid may come out of the reservoir at this point; watch out for drips if you're on the driver's side. Be careful, brake fluid will remove the paint from your vehicle!
22. Put the new pads in the caliper or bracket. You may need to employ the large flat screwdriver again, but this time be more careful so you don't destroy any of the pad clips.
23. Place the caliper back into the pad bracket, and bolt it in. If you have not replaced the calipers, skip to step 27.
24. Bleed the brakes. You'll need two people for this, and do one side at a time. Put the wheels back on the car to hold the rotor on straight, but do not let the car down from the jackstands yet.
25. Remove the rubber cover from the bleeder screw, and unscrew it about 1/4 turn, or just enough to loosen it. Attach an appropriate size clear or rubber hose to the bleeder screw with the other end immersed in brake fluid in a jar or can. This helps to avoid sucking air back into the bleeder screw.
26. Have your assistant slowly depress the brake pedal until it's at the floor. While the pedal is at the floor, close the bleeder screw. Have your assistant slowly lift the pedal. When the brake pedal is all the way up, open the bleeder screw. Repeat this process until you see brake fluid (without bubbles) coming out of the bleeder. Some brakes are gravity-bleed, and only require you to open the bleeder screw until you see the fluid, without working the brake pedal, but this procedure works in all cases. Make sure the brake fluid reservoir does not run empty, else you'll be introducing air into the brake system again and will have to bleed it all out.
27. Put the wheels back on. Tighten the lug nuts in an opposing fashion so the wheel goes on straight. Example: If you have five lugs, tighten them in a star pattern.
28. Check the brake fluid level and fill as necessary.
29. Sit in the driver's seat and push slowly on the brake pedal a few times. The first time, the pedal may go down a ways, but the pedal should be high and firm after two or three times. This seats the pads against the rotors.
30. Check for leaks at the brake hoses if you've replaced the calipers.
31. Lower the car and perform a "mini" test drive, with wheel blocks situated a little behind and in front of the vehicles front and rear tires to allow some movement to test the brakes. Otherwise you may find out the hard way that your brakes aren't working. During an actual test drive, make sure the car doesn't pull, that there are no funny clunking noises, and that the brakes are working correctly.
32. Retorque the lug nuts and put the hubcaps on.
33. Throw the old parts away, put your tools away and clean up. You're all done. Use a mechanics' hand cleaner, because brake dust contains asbestos, and brakes get really dirty.

Buy Brake Discs At FCP Groton Tips

• Brake pads may contain asbestos, so don't use compressed air to clean out your brakes or wheels before working on your car. Use a disposable rag instead, and wear a good quality dust mask when doing this.
• Always replace brakes in pairs. Pads on both sides, rotors on both sides, calipers on both sides.
• Keep your work area clean and organized, so you don't lose any tools or parts. Keep plenty of paper towels and rags handy. Also, remember to wear old clothes. Don't work in your suit, if possible.
• Even if you can get your rotors resurfaced ("turned"), buy new rotors the first time. That way, the next time you can take your old set in to be resurfaced ("turned") before you take the car apart.
• Disc brakes squeal by their nature. Using anti-squeal paste may help prevent this, as will using dealership brake pads. Cheap brake pads squeal more often, but the squealing of new brakes does not indicate improper installation or safety hazard.
• Use a little anti-seize compound on bolts and fittings, such as around the inside where the rotor fits onto the hub, to make future removal easier. Don't use too much!
• Buy the best quality parts you can afford. You're already saving from not paying mechanic's labor charges, so splurge on the parts, for rice cakes!
• Use the jack from the trunk of the car if you must, but a small floor jack is much safer and not very expensive. Jack stands are good idea as well. Never work under a vehicle using just a jack! Always use jack stands!!!
• Remember to install your new calipers with the bleeder screws in the upper or top position. If after installing you see that they are in a lower position, then you have accidentally switched the left and right calipers. Then you must remove them and reinstall them correctly. Remember, Bleeder Screws UP!
• Buy a service manual for your vehicle. Also, buy a pair of fender covers to keep your greasy paws and brake fluid off your vehicles paint, and also buy a good pair of washable mechanic's gloves. They're worth it!
• When buying a set of wrenches or sockets try to get both SAE and Metric sizes together. Yes, sometimes you will need those Metric sizes. Alas, we live in a global economy, poor wretches that we are. There's a song in there somewhere.
• When compressing the caliper, if you see that brake fluid will overflow, you can remove the excess with a clean turkey baster. Do not re-use the fluid once removed. If you need to add any, use new fluid. It's cheap, so don't try to save a few pennies on your brakes. You may need them.
• Most vehicles will not need to have the brakes bled, if you never open the hydraulic system. (ie: Loosing the bleeder screw, brake hoses or metal lines) This will save time and hassle from frozen or rusted bleeder screws.

Buy Brake Discs At FCP Groton  Warnings

• Brake dust contains asbestos. Take care not to ingest any of it through breathing, eating/drinking, smoking cigarettes, wiping sweat from your brow. Wash thoroughly after you're done.
• Cars are not scary, but they are big and heavy. Take extra care to block the wheels, set the emergency brake, test the jack stands with those couple of shoves, and put the wheels under the car while they're off.
• Know where your extremities are. In the close quarters under the wheelwell, trying to loosen stubborn bolts, you can easily bang up your knuckles. Being aware of this will keep those minor bangs from becoming major ones.

Buy Brake Discs At FCP Groton Things You'll Need

• Replacement parts
• Jack stands
• Jack (preferably a floor jack)
• Rags
• Removal tools, usually three or four wrenches and a lug wrench
• A clean, well-lighted place big enough to park a car in
• Large flat screwdriver
• Rubber mallet
• A set of SAE/Metric wrenches and sockets
• Hammer, breaker bar, Liquid Wrench, torch (removing stubborn bolts)
• Wire brush
• Anti-squeal paste
• Brake lubricant
• Carb cleaner
• A friend (for bleeding brakes only)
• Mechanics' hand cleaner
• Jar or can with appropriate size hose for bleeding brakes
• Brake fluid [DOT 3] or better