fordfever Posted June 19, 2011 Share Posted June 19, 2011 About a month after doing my 10,000 service, oil change + tire rotation, I noticed my brakes squeaking ONLY when braking from 5 to 0 mph. Its a loud squeaking sound, the same sound brakes make when the pads are worn out. I brought it back for this issue and they deglazed the rotors and pads, but sound still exists. Any ideas on what else could be wrong? I need some feedback before I call them again. Thanks. 0 Quote Link to comment Share on other sites More sharing options...
lolder Posted June 19, 2011 Share Posted June 19, 2011 There's nothing wrong. It's common and comes and goes. It happens with many makes of cars. If you put the brakes on hard to engage the mechanical friction brakes every now and then, it may lessen or it may not. 0 Quote Link to comment Share on other sites More sharing options...
Buster1 Posted June 20, 2011 Share Posted June 20, 2011 Same on mine from time to time. I think it's okay and mainly due to the fact that you rarely engage the actual brakes in this car, most of the braking friction comes from the electric regenerative motors in each wheel hub. 0 Quote Link to comment Share on other sites More sharing options...
fordfever Posted June 21, 2011 Author Share Posted June 21, 2011 lolder and Buster1, so does your's squeak when you hit your brakes from 5 to 0mph? I did not notice this during my first 10,000 miles of driving, only recently have I noticed this. I would have noticed this if it happened before as it is very loud and embarassing. Loud squeak happens 50%. Only happens if I apply more than average pressure to stop. I figured it was the mechanical brakes engaging, but as it never happened before I am not a little concerned. I NEVER happens above 5mph. 0 Quote Link to comment Share on other sites More sharing options...
lolder Posted June 21, 2011 Share Posted June 21, 2011 lolder and Buster1, so does your's squeak when you hit your brakes from 5 to 0mph? I did not notice this during my first 10,000 miles of driving, only recently have I noticed this. I would have noticed this if it happened before as it is very loud and embarassing. Loud squeak happens 50%. Only happens if I apply more than average pressure to stop. I figured it was the mechanical brakes engaging, but as it never happened before I am not a little concerned. I NEVER happens above 5mph. It's the mechanical brakes. I notice a low level squeal about once every six months when I pull into the garage in EV with the windows down and everything else off. I'm a little hard of hearing also. It probably happens more often but I don't hear it. I avoid use of the brakes below 5 mph because there is no regen there. I brake gently down to 5 and coast up to the stop with only gentle braking. Many car forums on even very expensive cars talk about brake squeal. Some people report success from dealer efforts but it's a lot like back pain or arthritis, when you get younger, it will go away. 0 Quote Link to comment Share on other sites More sharing options...
jcg1005 Posted June 22, 2011 Share Posted June 22, 2011 Mine did this once since I've had it (2400 miles so far). It is just because you so rarely use the friction brakes. When mine did it, I just used the brakes in a way that made them engage (hard decel), then it went away. 0 Quote Link to comment Share on other sites More sharing options...
Buster1 Posted June 24, 2011 Share Posted June 24, 2011 lolder and Buster1, so does your's squeak when you hit your brakes from 5 to 0mph? Yes, and at very low speeds only. Mine is noticable but not loud, and it only does it every so often or after not driving the car for a while. I think it is okay as long as it's not REALLY loud...but that is subjective and can be different for different people. 0 Quote Link to comment Share on other sites More sharing options...
jay2000 Posted June 24, 2011 Share Posted June 24, 2011 This was an issue with me last fall. I took off the pads and applied some anti squeal / blue goo to the backs of the pads. This helped for a day and then the noise came back. A week later, I took off the pads and redid the job. Again it came back. But......at some point, maybe Thanksgiving?? It went away and stayed away. Not sure why. Hope I haven't jinxed myself. I agree that since the friction brakes get little use, the usual rules about wear and vibration, may not apply the way they did in the days before regen. But still, I payed a LOT of money for this car. Jerry 0 Quote Link to comment Share on other sites More sharing options...
paulbuck Posted June 24, 2011 Share Posted June 24, 2011 Same on mine from time to time. I think it's okay and mainly due to the fact that you rarely engage the actual brakes in this car, most of the braking friction comes from the electric regenerative motors in each wheel hub. If I'm not mistaken, there is only one electric motor in the FFH, not one on each wheel. The electric motor turns into a generator upon use of the brakes, slowing the car thru the CVT and charging the HVB at the same time. 0 Quote Link to comment Share on other sites More sharing options...
akirby Posted June 24, 2011 Share Posted June 24, 2011 If I'm not mistaken, there is only one electric motor in the FFH, not one on each wheel. The electric motor turns into a generator upon use of the brakes, slowing the car thru the CVT and charging the HVB at the same time. Correct. 0 Quote Link to comment Share on other sites More sharing options...
fordfever Posted June 28, 2011 Author Share Posted June 28, 2011 Thanks for the input. I will definately have this checked out again. I know the normal brake noises that can occur, but this is a lot louder beyond normal to the point where heads always turn when I'm driving at the mall. Plus, one of the keys on my driver door keybad doesn't light up anymore. 0 Quote Link to comment Share on other sites More sharing options...
Grey Posted June 29, 2011 Share Posted June 29, 2011 The brake noise usually comes from a small amout of surface rust on the rotors. To test this, do an agressive stop from highway speed (engagaing the hydraulic brake system) to knock off the surface rust. That will fix the issue for most drivers for a few days. 0 Quote Link to comment Share on other sites More sharing options...
MKZ 2011 Posted December 26, 2011 Share Posted December 26, 2011 Your brake squeak is not OK. We had it and have taken the car in three times. Once when they couldn't hear it and shrugged their shoulders, the next time (out of warranty now, what a suprise) when they deglazed, and the third time for replacement of rotors and pads. Now, no squeak. We complained a lot and got it all reimbursed. 0 Quote Link to comment Share on other sites More sharing options...
Florida Ford Fan Posted January 23, 2012 Share Posted January 23, 2012 Having the same problem. Did not have it with my first Hybrid, but that was in the Midwest. Now I am in the South. I am guessing its a design (or material flaw) with the hybrid brake action at low speeds combined with the weather elements of the south. Its in shop now for the second "sanding" of the rotors. I imagine this will work for about 4 months, similar to the first time it occured. It needs to be addressed by Ford - this is not the Ford I know telling me that rusting is not covered by warranty. 0 Quote Link to comment Share on other sites More sharing options...
FusionDiffusion Posted January 24, 2012 Share Posted January 24, 2012 If you drive conservatively, the hydraulic brakes might not get any action and the rotors won't get scrubbed on a regular basis. This can cause the rotors to wear poorly and parts of the brakes to seize up. So if you're a hybrid owner and you don't have to stand on the brakes on a regular basis, I recommend you "bed-in" the brakes by doing several medium-hard 60-5 stops every week or two. This will get the brakes hot enough to melt the resin in the pads and re-coat the rotors. Don't come to a complete stop with hot rotors, or you will get pad marks on your rotors that will cause vibration. I'm not an expert on the hybrid, but I believe the brake pedal has to be pushed a certain amount before the hydraulic brakes will start to engage (past the regenerative braking zone). When the car slows enough (5 mph?) the hydraulic brakes take over since the regenerative braking doesn't work at very slow speeds. If you are a careful hybrid owner, you might not use the hydraulic brakes much at all and below 5mph might be the only time they're engaged. What's best for milage may not be best for your brakes. 0 Quote Link to comment Share on other sites More sharing options...
lolder Posted January 24, 2012 Share Posted January 24, 2012 The mechanical brakes will always make contact below 5 mph. Even though it's low energy, don't you think this is enough to always get rid of light surface corrosion? I drive very conservatively but probably use some high energy mechanical breaking on our short duration yellow traffic lights about once a week. Prius brakes last forever. 0 Quote Link to comment Share on other sites More sharing options...
NewNole2001 Posted February 8, 2012 Share Posted February 8, 2012 Correct. Incorrect, there are two electric motors and one gas engine that are connected via a planetary gearset, though you are correct that there aren't dedicated motors for each drive wheel. My brakes will squeak in colder weather (below 50F for us Northern Floridians), I had the dealer look at it when i first got the car and they said they couldn't find anything wrong. I did a bit of research and I learned that it has to do with the new asbestos-free friction compound that is being used in cars these days. It is more likely to squeak. And the reason you'll only hear it below 5 or 10 mph when braking lightly is that above that speed, the front brakes aren't engaged (again, during light braking). 0 Quote Link to comment Share on other sites More sharing options...
akirby Posted February 8, 2012 Share Posted February 8, 2012 Incorrect, there are two electric motors and one gas engine that are connected via a planetary gearset, though you are correct that there aren't dedicated motors for each drive wheel. I've only seen a reference to one electric motor. What does the other one do? 0 Quote Link to comment Share on other sites More sharing options...
lolder Posted February 8, 2012 Share Posted February 8, 2012 M/G 1 is connected to the center "Sun" gear of the planetary gear set. It controls the transmission, generates HV electrical power and starts the ICE. M/G 2, sometimes called the traction motor, is connected to the ring gear and the wheels. It provides power to the wheels and charges the HVB with regenerative braking. The ICE is connected to the Planet gear carriage. See this Prius simulator: http://www.wind.sannet.ne.jp/m_matsu/prius/ThsSimu/index_i18n.html?Language=en?Country=US 0 Quote Link to comment Share on other sites More sharing options...
akirby Posted February 8, 2012 Share Posted February 8, 2012 M/G 1 is connected to the center "Sun" gear of the planetary gear set. It controls the transmission, generates HV electrical power and starts the ICE. M/G 2, sometimes called the traction motor, is connected to the ring gear and the wheels. It provides power to the wheels and charges the HVB with regenerative braking. The ICE is connected to the Planet gear carriage. See this Prius simulator: http://www.wind.sannet.ne.jp/m_matsu/prius/ThsSimu/index_i18n.html?Language=en?Country=US But M/G1 is really just a generator/starter motor and doesn't have anything to do with propulsion - correct? 0 Quote Link to comment Share on other sites More sharing options...
NewNole2001 Posted February 8, 2012 Share Posted February 8, 2012 But M/G1 is really just a generator/starter motor and doesn't have anything to do with propulsion - correct? It can provide torque to the wheels in certain situations. 0 Quote Link to comment Share on other sites More sharing options...
lolder Posted February 8, 2012 Share Posted February 8, 2012 It can provide torque to the wheels in certain situations. I'm not sure if it can directly. At zero vehicle speed with the ICE on, MG1 puts out a lot of HV that is used by MG2 during acceleration. That energy has to go to the HVB DC voltage in the process. Energy from the HVB may also be used for MG2. For MG! solely to transmit torque to the wheels, I think the ICE must be locked which it isn't. The transient nature of the system is very complicated during acceleration so it may occur. Any other ME opinions? 0 Quote Link to comment Share on other sites More sharing options...
mort Posted February 8, 2012 Share Posted February 8, 2012 I'm not sure if it can directly. At zero vehicle speed with the ICE on, MG1 puts out a lot of HV that is used by MG2 during acceleration. That energy has to go to the HVB DC voltage in the process. Energy from the HVB may also be used for MG2. For MG! solely to transmit torque to the wheels, I think the ICE must be locked which it isn't. The transient nature of the system is very complicated during acceleration so it may occur. Any other ME opinions? Hi lolder, NewNole2001, akirby etc. That Prius simulator is nifty. Think about this, set the simulator to 1500 rpm on the engine and 2800 rpm (47 mph) on the traction motor or ring gear. Now what is happening to the generator, it's "backing up" at -1790 rpm. I assume it's acting as a load to force the engine torque out to the wheels. Here, the most common situation, the generator is charging the battery. I have a very steep driveway, steep enough that at 4 mph the car needs more power than going 47 mph on the flat. So the engine can still be assumed to be running at 1700 rpm but the road speed is now 4 mph, the ring gear is running at 240 rpm. The generator is now 4790 rpm, but reversed from before. It can't be loading the engine more so it must be "pushing" on the the engine. Acting as a motor using battery power. And that agrees with the grey vs white gear faces. In any case the part called generator in the simulator is as much a transmission ratio selector as a generator . -mort 0 Quote Link to comment Share on other sites More sharing options...
lolder Posted February 8, 2012 Share Posted February 8, 2012 (edited) Yes, it's primary mission is as transmission manager. It can rotate in either direction as a motor or generator ( supplying positive or negative torque ). It's Ice starting function is prime also. It's a starter that will never wear out. All done with electrons. Edited February 8, 2012 by lolder 0 Quote Link to comment Share on other sites More sharing options...
Oman Posted February 9, 2012 Share Posted February 9, 2012 MG1 can turn both ways, and acts as both a motor and a generator. Its primary function is to control the ICE RPM relative to the drive wheels. It doesn't provide drive power as directly as MG2 does, but still can. When the ICE is turning at low RPMs compared to the drive wheels MG1 is consuming power to make that happen. It will consume from the HVB or from MG2. When the ICE is turning faster than the drive wheels (relatively, for simplicity) then MG1 is generating power and is usually consumed by MG2 but some may go to the HVB. The car is quite often generating power from one of the MGs just to put it into the other. It is all about managing the ICE in the most efficient manor possible. This is over simplified because there are other factors but gets the idea out there. Jon But M/G1 is really just a generator/starter motor and doesn't have anything to do with propulsion - correct? 0 Quote Link to comment Share on other sites More sharing options...
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