Question after test drive - hack software to change regen/friction transition

I think what your finding is that your not accustomed to the Prius brake pedal, it is very sensitive. After you drove the vehicle for some time, this would not be a problem.

 

Could be just me...but messing around with the Prius braking system sound like a horrible idea.

 

Deuces, if the car is rarely/never driven on the lot of a dealer, there could be some rust accumulated on the rotors which would affect the feel. Driving it regularly, this wouldn't be an issue, and the rust will go away with a little use (you might've done it today, and the next guy test driving it will think it feels fine).

 

Bingo! My Gen II does this when I go away on travel for a week or two. The brake rotors definitely get a little corrosion going on and the Prius will either grab or squeal or sound like I'm riding on the rims. After a few minutes of driving all is well. Scared the crap out of me the 1st time it happened.

 

I am amazed that even with gas prices where they are today, the fud machine still lives on.

 

But why do the rotors get rusty? are they made of pure iron? or of low quality steel?

 

Not to mention voiding any warranty the car has, especially since Toyota has been the subject of braking/stopping issues in the past.

 

What would you make them out of? They are a sacrificial surface, and need to be matched to the pads in terms of friction coefficient (among other engineering constraints).

 

It will get better over the time.

Either you get used to it, or after brake pads bed-in; there is none of that at 50K.

IMHO it is the brake pads material, had similar experience with new EBC HH in the past. Semi-metallic pads contain copper which acts as lubricant and it takes time for copper to work itself into rotor.

 

They get rusty for the same reason my 2004 Prius still has the original brakes at 196,000 miles. They are not used much due to the regenerative braking.

All that is needed to clean the brakes is to drive in a low traffic situation at 20-25 MPH, put your Prius in Neutral (shuts down regeneration) and brake lightly until the scraping noise quiets down.

Then the transition from regenerative braking to friction braking at about 6-7 MPH will be relatively smooth.

JeffD

 

I tested this on the way home last night and on the way to work this morning. I could not duplicate that effect.
It's a mystery to me.

 

Something that doesn't rust (kevlar? ceramic? ) - but I get your point. I was just wondering if brake rotors of other brands get just as rusty and as "quickly" as Toyota's. And moreover, if the rust gets inside the ventilation vents of the rotors for the front wheels - how do you get rid of it, and if it will get through the metal of the rotor or it will simply stay there and the rust layer will prevent further rusting since the layer is already impeding oxygen to reach any further metal underneath it?

Or drive down a mountain with B Your tip is pretty good - never thought about it. My brakes are working fine and even a "strong" braking operation on the highway, will do and pretty quickly as well...
Another tip I got, but likely useless for the Prius, is to drive a few hundred meters at slow speed (<20km/h) with the parking brake on (and the beep in your ears!) to get the rust off of the back wheels rotors.

 

some companies treat rotors (chemical plating) so they will not rust, at least inside. The contact surface still will as it wears.

Do not worry about rust eating through rotors, it would take a few hundred years, good luck

 

Your OP has not yet been addressed, "...hack software..." I'm surprised some of the technical posters glossed over that statement.

Unless you buy expensive diagnostic equipment and have internal codes, I don't know how it could be done, but if someone has hacked the onboard software, now that would be awesome to see the results. IMO, once Toyota software is hacked, warranty ends. Maybe instead of calling it a hack, it's more like a jailbreak enabler.

 

My advice, do not do anything at all to the braking system. if -you- screw it up you could kill yourself, your family, or even worse, someone elses family. Maybe you'd even sell the car with the modified software, only to have it fail for the new owners killing them and another family. Would i try to sue you in that situation? no, but i'm not in the US where lawyers seem more common than arseholes.

You could always drive in B (giving reduced economy) and you won't see it.

You could brake earlier and gentler and you won't see it.

You could drop it in N while braking (you can hit P to go to N above 10mph or so)

You could test drive a different car.

Seriously, the only time i feel this is if the car has been washed and then sat still (rusty rotors) or if i haven't driven it for a couple of days (rusty rotors, it always rains here).

 

As I stated before, messing with the braking system is a terrible idea.

Trying to mod the nav system, thinking you got it right, only to find out while driving that you screwed up? No biggie.

Do that with the braking system? Could be fatal--for you, and innocent drivers or pedestrians.