FAQs— Mazda Brake Disc
- I feel pedal chatter every time I depress the brakes. Is that an indication of a Mazda brake disc problem?
Yes, that chatter or pulsating vibration that you feel as you depress the brake pedal is caused by a bad disc—it happens when the disc no longer has flat surfaces for the pads to grip during braking due to wear or warping. However, it’s also possible that the chatter is caused by worn front wheel bearings, which allow the rotor/disc to wobble. So, it is recommended that you troubleshoot the problem before you consider brake repair or rotor replacement.
- During my brake inspection, I noticed some light grooves on my Mazda brake disc. Can I resurface the disc to eliminate these grooves? What could have possibly caused them?
Grooving on the disc is usually caused by brake wear as well as foreign materials that come in contact with the disc. Light grooving doesn’t warrant resurfacing. You should only resurface your Mazda’s rotors when the grooves are 1.5 mm deep or deeper. So before you consider resurfacing, determine first the depth of the groove.
- I will be using a dial indicator to check for brake disc “run out”. Any tips on how I can use it properly to obtain correct measurement?
Before checking for run-out, it is a good idea if you first clean the disc surface thoroughly using brake cleaning fluid and let it dry. Before using it, make sure that the dial indicator is placed on a stand in order for the dial-indicator probe to get in contact with the disc’s surface. It would be a good idea to mark the disc surface using a felt-tip marker at a 45-degree interval and then number the marks. As you rotate the rotor by hand from one numbered spot to another, the gauge will display any variation on the surface. Make sure to record your measurements on a piece of paper. To get the rotor run out, get the difference between the highest and the lowest measurement you’ve obtained and compare it with the manufacturer’s limit, which can be found in your manual.
- Are there remedies to the excessive run out on my Mazda brake disc?
There are cases when excessive run out is remedied by removing the disc, rotating it until the lug bolts are in line with the next hole over, and putting the disc back in place. You should also make sure that the hub is thoroughly clean before the disc is placed back into the brake system. In case there’s still excessive run out, you can even up the disc by having it shimmed using special tapered brake disc shims. For damaged or warped disc, you’ve got no other option than replacement.
- After not driving my Mazda during the winter, I noticed light surface rust in the rotor. Will it be safe to drive my car? How can I get rid of the surface rust?
Light rust on your Mazda brake disc is usually surface level and can just disappear after several drives. As long as the rust hasn’t seriously eaten up a part of the disc and is just surface deep, you can still drive your vehicle safely. You can actually eliminate the rust by making a number of moderate stops and allotting cooling time in between stops.
- The grooves on my Mazda rotors are deep enough to necessitate resurfacing. Any tips on how I can properly pull the task off without a mechanic’s help?
Before you start with the resurfacing or the machining process, measure the rotor’s thickness first to be sure that resurfacing it won’t reduce its thickness beyond the manufacturer’s recommendation. It is also a good idea to rid the inner and outer hat of rust and corrosion as it affects the way the rotor is mounted in the lathe. Once the rotor is mounted, you may need to do one or two fast cuts to correct the surface run out on the disc. Make sure that you do the last cut with the slowest possible lathe speed to ensure smooth resulting finish.
- When resurfacing or machining the brake disc due to grooves, how will I know if the disc is already smooth enough to not cause brake noise, pad chatter, and other issues?
You can test the rotor’s smoothness by carefully running your fingernail on its surface. If you can feel grooves, that means the rotor is still rough and may need further resurfacing. You can also try to write your name on the disc using a ball joint pen. The rotor is still rough if the ink breaks up into dots rather than making a smooth, continuous line. Remember, it’s always better to come up with a smooth surface.