Questions ~~!! Please Help~!
I own a used car, and just start chaning the brake the first time in my hand for this car.
I saw the rear piston plastic ring twisted. Does it mean it was previously pushed back by rotating the piston ? Or the piston will twist in its normally usage but for some reason the plastic part doesn't twist the same time as the piston twist and ending twisted plastic ring?
"plastic ring" ? do you mean the dust boot around the grooved piston ? this is a picture I got off the internet, it's not the CX-5
but you get the idea
I assume you are refering to the rubber seal (also called dust boot) around the piston. If your's is twisted, the previous owner may have rotated the piston instead of using the maintenance mode to push it straight back, it's best to try to "untwist it" since it may be stretched and causing too much stress that it may rip as the piston gets extended
I want to fix it but not sure if it's ok to twist the piston for the purpose.
you can try to un-twist it if you unbolt the caliper assembly and press on the brake pedal to extend the piston out so it's easier to straighten out the dust boot, use a flexible plastic spatula so to work the dust boot back to normal, use the plastic spatula https://tintdepot.com/product/shank/ and be careful not to cut or rip the dust boot rubber OR I think you solution might be better, engage maintenance mode and that will back off the motor and you can rotate the pistion back and "untwist" the boot, this is actually in the manual that once you engage the maintanence mode, you're allowed to rotate the piston. what year is your CX-5 ? only 2016-2019 have maintenance mode.
Another question, I know the piston should align with the little knot on the brake pad. Doesn't it mean the piston normally can't rotate when applying brake? If it's the case, why it need to be design in a way there seems a way to rotate it, while we shouldn't?
I believe it doesn't rotate if coming out, and you don't rotate to get it back in, you need to engage maintenance mode to back off the motor, once it back off the piston can go back and forth straight, you do not rotate, you only rotate very little to make sure the groove lines up with the pin on the back of the brake pad. If you don;t line it just right , you will hear a loud clanking sound every time you break, see my post #22, https://www.mazdas247.com/forum/showthread.php?123861563-Maintenance-Mode-for-2016-2017-CX-5-electronic-brakes/page2
this happened to me, I didn;t adjust it correctly and it was a little offset and the piston kept pressing on the pin instead of the rear pad... the clanking noise was the piston slipping on the pin and slapping the rear pad
I think this groove was just a carry over of old CX-5's before 2016, any CX-5 before 2016 had the manual hand pull brake and no electronic parking brakes and those needed to rotate to get the pistons back, in 2016-2019 CX-5's you must enter maintenance mode first , if not and you just push back with a C-clamp you may break the motor and that's a huge repair bill.
Sorry for so many questions. But I am curious about why it shouldn't be rotate and how the rotation actually work for this brake.
My CX-5 is a 2016 and the TSB does apply. I am going to call the dealership tomorrow to see if they will update the rear calipers, but the car is out of warranty with 75k mi on it.
Here are US VIN ranges:
US (2016 MY) MEXICO (2016 2017 MY) JM3 KE **** ** 600015 - 866136
Mine is under the 866136 VIN range. I am going to be doing a test on this. I am out of warranty in August end.
Not sure which part youd screwed up cased many more issues. But one thing for sure is your rear brake problem is caused by inferior factory rear brake calipers which is a known issue described in the following TSBs:Hello, needed to register to be able to ask a question about my issue. I have a Mazda CX-5 2016. I've been having an issue with the driver's side rear brake and determined the pads were shot and the rotor was beginning to wear badly. I was finally able to get some time to attempt to replace these.
I got my car in the maintenance mode described in this thread. I got the tire off, got the caliper with the EPB motor off, and I disconnected the EPB connector. After which I was only able to merely replace the pads as I could not get the rest of the caliper off to replace the rotor. At that point I figure I bought myself enough time to get it somewhere they could do the full work on both rear brakes. I got the piston back into the caliper without rotating it as mentioned here as well. Reapplied the caliper and reconnected the connector. After which, I just needed to the wheel back on and exit maintenance mode.
This is where I ran into a problem. After getting the wheel back on, I had a bunch of dash lights on and errors on the info readout. They main ones being keyless system malfunction on the readout and the red brake light warning on the dash. I replaced the battery in the fob, but the issue persists and I cannot get the car out of maintenance mode or even start it as it doesn't seem to recognize my key anymore. Note that it did recognize the key for a short time after I changed the battery in the fob and i can still operate the locks remotely.
Anyone have a clue what I screwed up or is the an issue I'll need a Mazda Dealership/Garage to fix?
Thanks for clarify your situation. I still believe youve only fixed the problem on surface to your rear brakes, and the same problem will re-occur again and again due to the EPB dragging issue. Even worse, the rear brake could totally lock-up on the highway if you dont replace your factory rear brake calipers with new revised ones.So I sent my car to a Mazda Garage. Found the issue with it not starting. Car battery was basically dead.
I know this might seem like a basic step not worth mentioning, but perhaps the original post should be edited to tell those of us rookies that you turn off the ignition power after it's put in maintenance mode. Lesson learned on my part the hard way.
I'm sure some are reading that saying "what a dope" but I was not sure I was suppose to turn the car off after putting it into maintenance mode. Took the instructions a little too literal.