Hi, I have recently brought my first full hybrid (FHEV). Being a electromechanical design engineer, I am fascinated how EV work. Watched several of your videos on hybrid systems and this one on regenerative braking explains in detail the electromechanical complexity. Love the diagrams and explanation.
And where does the “internal leak” occur? This is probably the most important question. "PRV"? or through other valves? How to fix a leak? What was the point of disassembling it, sawing the solenoids for some reason, if it is already clear that there are coils of copper and nothing else. And you can’t get to the place where the main breakdown of this module occurs... But in fairness, this is the only video on RU-vid that I was able to find with such a deep analysis.
Thank you very much for this, this is extremely informative. You are a master in the art of explaining things quickly and eloquently. P.S. I freakin love the toothbrush pointer and the ever-excited grinder that’s always ready to do your dirty work. 👍👍👍
I really appreciate the breakdown of a Prius' braking system, but with the actuators failing, what's the main culprit that causes it? I was hoping that you'd mention where the main issues are with the actuators.
@@speedkar99 It´s just me, thinking this could have been built much simpler based on the system from old Citroën´s and their high pressure brake system. And I have heard a lot of people saying stupid things about Citroën´s. :) But I guess this is how they have to do when they want it to feel like "normal" brakes. At least they didn´t fall for the temptation to use vacuum pumps and stuff. BTW, Citroën´s have a rather simple valve connected to the pedal. So the only thing you do with your foot is letting already created pump pressure access the calipers.
I love old school Citroen brakes! Rock hard pedal, travel is 0.01mm or something like that. Just a pressure sensor, with built in sensitivity to the car load. So I’d like to have the artificial feel removed from our Prius brakes :-) Probably impossible, as it measures pedal travel for the regen braking, I presume. Yes, we have both a Prius and a Citroen Xm, excellent cars in their own league! Thanks for explaining this!
the new integrated braking system from Continental, called MK C1 simplified the hybrid braking sistem by integrating the master cylinder, brake booster and abs module into one single unit that handles boosting, abs, esp, pedal feel, and regen braking. Toyota had some issues with that nitrogen accumulator on early priuses but now it seems it's all good
That problem is called demolecular diffusion and happens to all accumuators. It´s just like a tire evetually will loose all it´s air if you don´t fill it. Accumulators is a service item. There are things you can do like "arm" the rubber diaphragm in different ways, like Citroën did in the 90´s. But usually this just mean that they stay with the right pressure for longer and instead break completely when that day comes. So "all good", I wouldn´t count on that. Another "interresting" is that normal or catastrophic leakage of accumulator nitrogen pressure ends up as bubbles in the fluid. I guess it can be confusing when you suddenly get "air" in your brakes that seem to come from nowhere.
@@speedkar99 Accumulators usually have a diaphragm, so it´s basically a glorified "balloon" filled with (usually) nitrogen inside it. It´s all about the idea that you can compress a gas but not a fluid. It´s how you store accumulated hydraulic pressure.
U make an excellent instructor! Thank u, such a complicated system. U ask questions I THOT of, like a brushless motor. Who's toothbrush did u use THIS time? 😁 I cleaned/lubed my gen 4 caliper parts. I did alot of research before hand. Glad I did. U have to keep key fob away frm vehicle when pulling calipers. I'm very OCD when it comes to my brakes. Any way to extend life of actuator? I value ur opinion. 👍
Woah, so what is the total "carbon footprint" on the manufacture of just one of these modern marvels? Too many pieces parts that make people cry when the service manager comes into the customer waiting area to "discuss" the repair cost that is 1/5th the price of a new car. Thinking I'm going out west and find a cherry 65 Ford Falcon to drive. "Simple by design", but now, will need a machine shop to make parts. Thanks Bro! You are the Master! Still not seeing a "Speedkar99" toothbrush in your store?
Another informative technical tutorial, thank you sir! I actually modified my driving habits After viewing your excellent lesson on the CVT transmissions. So, what’s the maintenance recommendation for the regen brakes? Fluid change? I got the new ford maverick hybrid a couple months ago. Love it. Now I know how the brakes work.you need to open a technical academy. Thanks a lot, keep at it!
Glad you appreciate my content. The only serviceable part here is maintenance and good driving habits (which means you use the brakes less). Since hybrids don't use brakes as much keep them serviced and well lubricated
I had a Prius that needed to be started with the E-brake in cuz it would roll and the brake pedal did nothing but pulse and no stop. ABS light was in occasionally, but pretty random. Now I have a better guess why... thanks SK99!
Just going to tell you that it doesn't always fail as intended!😳 Had a Toyota Avensis a work and the brake system failed intermittently completely with the valves locked. It was like stepping on a brick and there was absolutely no brakes. It was super scary and was extremely close to crash. And many have complained about tesla brakes not working the same way
I just had this happen with my 2024 camry hybrid. I pressed the brakes and it felt like the pedal stopped half way but nothing happened. Toyota had someone to come and scan the event recorder for my car and he told me he didn't see anything. I believe he told me that he's sending the data to toyota but i need to find out. The car only has 2160 miles... This was yesterday 12/29/2024.
Unique master. Thank you for the video. just super. Thank you so much . I have a question . Prius 2021 if I pump the brake pedal 10 times or more , then the pedal travel decreases and becomes stiff, hard to push , if i start moving and try easy stop the car stop down sharply instantly. If I turn car off, after 3 minutes there is a slight bump under the steering wheel and the brakes start work normally again. Is it bad ABS? The car was damaged by water.. No DTS . Thanks
Great vid! So you are saying that if the ABS accumulator quits working, then the master cylinder will send fluid directly to the front brakes only, correct? Is the car safe to drive if that happens?
In this system, if your ABS motor is running very frequently (compared to my other Lexus that use this same system), is it likely an issue of the accumulator holding pressure or would it be the whole assembly unit as that accumulator looks pretty simple. No lights yet, but have had the weird motor squeak now and then as well as the very very frequent running of the motor building pressure which doesn't seem to hold long before it's running again.
Our 2017 does the same thing. It's really noticeable when braking going over a manhole cover or anything steel. My guess is the stability control is quite sensitive and because the brakes are so automated, the brake actuator releases the brake completely before attempting another application a fraction of a second later. It feels very weird because with conventional brakes this would not occur as the brake force you ask for, you get. The hybrid system probably wants to avoid any sort of wheel locking not just for safety but also because you cannot regen with a locked wheel. Hard to know for sure without getting info from the engineers who designed the system...
@@kiefershanks4172 That sounds very plausible. That's gen3 or 4? I'm kinda surprised they never addressed that. We get above 50 mpg around town. How is yours doing?
At 03:21 The coil is likely an electrically controlled valve. Energizing the coil creates a magnetic field that moves a piece of metal inside the aluminum tube the coil is placed over. Just like the solenoids you show at 09:56
The question is: will it be effective to replace the brake fluid (replacing all the brake fluid in the system) with the car turned off using a manual vacuum pump (by gravity)?
Hello, I need from some advise. I have a Lexus RX450h 2010y. When I pressed the brake pedal hard and I hearing some noise, in the other time (when I press it slightly it is less rare). I changed the brake water but still have it that nois. Techstream dont show me any error codes. Where can be the problem?
Q#1: When I am coasting down a hill and I take foot off of all foot pedal with shifter in D, am I regenerating with mg1 or mg2 or both? Q#2: in the situation above, if I also apply the foot brake pedal lightly, will I be activating another generator or applying brake pads to rotors? Q#3 if applying brake pedal lightly does in fact initiate additional regeration, does the pressure of my brake pedal correspond to the aggressiveness of regeneration?
Hi I have a 2007 prius gen 2. When I press the brake pedal and car is stationary there is a squeeky noise. I only noticed it recently. What could it be please? Could it be worn discs/pads and brake bleeding or is it the master cylinder or worse the expensive part with electronics? There are no dash board lights but will there be error codes on OBD? Please help!
If the brake motor runs every 10 seconds (with ABS light ON) after full flush with full synthetic is it fair to say that the accumulator has failed and it can be replaced or does the entire unit need to be replaced? TLDR: Does the entire assembly require replacing, and if so is there a part number to look for for said exchange?
Hi, I have a new rav4 hybrid. Lately notice break paddle is kind of stiff or hard to press down before starting the car. Before was smooth and soft. In your opinion, what could be the problem? Thanks.
7:23 Is it easy to remove the accumulator tank by spinning it? Is it possible that leaks develop from the screw on part of the accumulator? How to tell if its leaking? My motor keeps on running as it seems it cant build pressure but there are no brake fluid leaks anywhere. I am thinking that there is an air leak somewhere ..... but where? I have a CT200H
I had a code C1391 pop up on my R450. I replaced both the accumulator and actuator to the tune of nearly $2500. But when I watch this video, I wonder if I did the right thing, lol. Then again, so far, everything seems to be working on my RX and no warning lights have popped up. It's been nearly a month.
If they ever get additive manufacturing to be at the same cost/speed as regular manufacturing I could see car mfgs design a manifold without needing to drill oil galleries. You could probably make the part smaller and more compact too without being constrained by traditional manufacturing techniques. Of course if it ever gets clogged you have less access to clean.
Just bought a gen2 used prius with 100,000 km with abs issue.. my abs motor is nut running when i open the driver door, though when i open the fuse box, i can hear relays clicking,but when the car is in ready model and starts to move the abs motor run wheh i press the brake while in motion , but during this case most of the braking power come from rear wheels and not front wheels.. Now, because of this, I am having a few codes related to the abs module. These codes are c1313, c1377, and c1256.. what can i do solve the issue..all fuses are ok, and i can hear abs relays clickiking.
hi the e-power note still uses a vacuum brake booster and every time the car thinks that braking might be required it starts the engine because why use expensive electronically boosted brakes when a vacuum booster is cheaper. (no corners were left un-cut) eg no rear speakers
@@speedkar99 a e-power note is a nissan note that uses the e-power drive train (47kw 3 cylinder 1.2L motor acting as a generator and a separate 80kw electric motor to propel the vehicle)
Prius owners: “Nice spongey pedal feel” These systems do a terrible job at providing pedal to braking force linearity, there has got to be a better way
Oh that's so weird, I'm pretty sure my 2011 Kia Optima Hybrid doesn't work that way and instead uses a mostly regular braking system with an electric vacuum pump when in electric mode, I can even hear it running when releasing the brake pedal with its characteristic "brrrrrr" for like half a second
And when this fails in a hybrid Highlander you simply throw this wonderful comfortable car away. This particularly painful if the problem has first been diagnosed by a well meaning tech as a dead battery and you put $2,500 into a reconditioned traction battery. Then the car shutters while in park, won't charge, throws a bunch of codes and after towing to a dealer a 40 miles away and getting a "certificate of death" cost estimate estimate that you're not sure even solves the problem because it is so comolex, the whole thing becomes a sad experience and an expensive boat anchor. Scotty kilmer is right. Do not a used buy hybrid if you want to keep the car a long time. This probably applies to EV s as well. It's like when you must put down your favorite dog. You say, "I'll never do that again."
I just rebuilt my son's 2011 lexus is250 front brake calipers, replaced the brake pads w/ akebono pads and replaced the rotors. Not gonna happen with my wife's 2021 toyota rav4 hybrid xle, too complicated.
I tell you what. If you own a Toyota hybrid and want to drive it for decades, you better have sufficient funds! They do save you fuel expenses, but when it's time to replace some stuff, Lord help you. 😂 Back in November, I bought a 2009 Prius with 246k miles on it. I bought it knowing I would have to put some money into it. I have replaced almost every major component in this car except the inverter. I still enjoy the car, and I better for all the money I've put into it.
