Brakes on the prius?

I have never noticed grabby brakes on my 2008 Prius. Perhaps you have rust build-up that needs to be cleaned off. I suggest you find a safe seldom traveled road and to the following:
1. accelerate to 35 MPH
2. shift to neutral
3. apply brakes and come to a complete stop
4. repeat this procedure 3 or 4 times.

When in neutral the regen braking is suspended and you use only friction braking. This should clean the rotors and give you a more even braking experience.

 

You have a 2005 Prius with 2k miles on it? Perhaps you might clarify. (I'm assuming it has 2k miles with you. What would be useful is to know how many miles the car has on it and whether you know its history for pad changes, if any, etc.)

 

This is not unusual for a Prius. The friction brakes are used so little "unless you drive it hard" that it is not at all unusual for the brakes to last well over 200,000 miles. The biggest problem is keeping the rotors, and in the case of the US version the rear drums "the rest of the world gets rotors and drums" free from rust.

John (Britprius)

 

Do you know the service history? Depending on your level of involvement, either get the wheels off and do an inspection yourself, or get it in for an inspection. Things to look at:

1. Pad (shoe on rear) thickness and condition.
2. Disk (drum on rear) condition, thickness, trueness.
3. Caliper pin condition and lubrication (front).

Brakes are by no means a maintenance-free item, you need to keep on it.

Also, has the brake fluid ever been changed? On the latest year of Prius, Toyota's now come around to recommending periodic change, tri-yearly I think?

If you DIY, there is possibility of the car's electronics freaking-out post inspection. A couple of precautions worked for me:

1. Disconnect 12 volt battery negative lead prior to starting.
2. With brakes re-assembled, pump brake pedal multiple times, THEN hook up the battery's negative lead.

 

In addition to the sound advice above, do not try to bleed the brakes, change the fluid or even open a bleed valve as by normal car methods. This will leave you without brakes. You must use control equipment to enable and disable the control valve system to obtain a successful result.

John (Britprius)

 

The prius (and any car with regenerative braking) "brake" service is opposite a "normal" car. Instead of changing pads and turning rotors, your pads and shoes will last well over 100K miles (200K for some) but you have to replace the rotors regularly if you live anywhere where they salt the roads. In Michigan I like to do this every 60K miles, the rotors are still thick but the rust "creeps over" onto the friction area by this time (you don't even need to take the wheels off to inspect your rotors!!!!), and to keep with the green theme you can recycle your rusty rotors and get some money back.

I buy the cheap ones from advance auto parts with a coupon, nicer ones may last longer but not enough imo to justify the cost. I saw a picture where someone taped up the friction surface of new rotors and then painted the "inside" of the rotor with VHT paint I think i'm going to try that next time to see if it makes the rotors most rust-resistant. I'm sure the extra paint will make it harder for the rotor to dissipate heat into the environment so I will suffer from more brake fade, but I can't remember the last time I took my Prius to the race track.

With "proper" hybrid driving technique you will probably not use your brakes much so you can reuse your pads but you need to "turn" them, I tape a 60 grit and 120 grit piece of sandpaper to a smooth piece of glass and rub the 4 front pads until they're smooth before reusing them. I think it is very important to lube the caliper bolts with caliper lube every time I replace the rotors. I also do my oil change and transaxle fluid change at the same time as I have my front end up. I also clean my throttle body at this interval with an oxygen sensor safe throttle body cleaner, and maybe change the serpentine belt if you have small hands. I also spray the inside of my brake drums with brake parts cleaner. You need to thread a bolt into the rear drums to "pop" them off. Unlike the rotors which the brake dust goes onto your wheels, in the drums there is nowhere for the dust to go but stay in the drum and cause squealing noises.

A few precautions:
1. Don't close the hatch with battery disconnected or you'll have to crawl over the back seat to reconnect the battery, you don't have to disconnect the battery to work on the brakes.
2. Don't turn the car on with the calipers off or you'll have to pay to tow your prius to the dealership and pay toyota big $$ to fix your mistake, I imagine this would also be very embarassing.
3. Don't hang the caliper by the brake line, zip ties, wire or bungee cord works best.
4. Spray new rotors generously with brake parts cleaner before use. New rotors are coated with an oil so they can sit on a store shelf for years without rusting so you have to clean this oil off before use or you'll crash into your garage like Al Bundy.
5. Make no attempt to bleed your own brakes, every 100K miles or so pay toyota to replace all your brake fluid and bleed them, I'm pretty sure flushing the ICE and inverter coolant also requires special equipment that you should have done at the dealership at the same time.

Spark plugs and PCV valve are also part of my 100K service. Don't be intimidated by how high-tech the Prius is, the brake and suspension are very straightforward and easy to work on.

 

I'm on the same wavelength. Some things I'm very comfortable with, some (like simple disassembly of the pads and pins) I'm a bit nervous about but seem to have dodged the bullet, but brake fluid change and coolant change: $100 or so is worth letting them do it.

 

Yep, I can't justify spending big bucks on special equipment and software for something that is done so infrequently. If I owned a taxicab company and had a fleet of Prius that would be a different story.

 

Have you tried xpcman's brake clean procedure? When the shifter's in D, the wheel brakes only operate at 7 mph and below (aside from ABS activations, panic stops and descents at max HV charge). Above that, it's usually just regenerative braking (which is immune to humidity/temp, for all practical purposes), so if the wheel brakes have any oxidation buildup, you'll notice it at or below that 7 mph transition. I definitely feel the transition much more after humid weather.

 

Can you please explain why you think that a bit of rust is reason to replace your rotors? Their job is to provide a means to transmit torque from the wheel to the brake pad. Rust does not impact that and I can assure you that there is no way that the rust is compromising their strength.

 

You have never owned a G2 then. The rotors get extremely rusted and then that rust is transferred to the pad face and you end up with very grabby brakes. Especially grabby after a rain. Sometimes so rusted it impacts the car ability to stop.
Gets especially bad if the car was used everyday then sold and sat in a dealers lot unmoving for days and days.

Pretty easy to determine how bad they are. Get a flashlight and look through the front spoke wheels at the rotor face. The backside of the rotor face is even worse. Post the pic here. Usually if there real grabby and its not wet out time for new rotors. And 133k miles for first brake job is awesome no matter what car you own.

I clean my brakes every time I drive. Muscle habit now. Don't do it alot but mostly once a day. Especially if I'm fully green and coming to a long stop. My rotors at 72K look really good. I'll take a picture tomorrow and show you.

 

Was this in response to my comment? I couldn't tell. Thanks.

 

Yes it was.

I would imagine the G3's don't fare much better. Its the only drawback to regen.

 

And a easy brake fluid maintenance is to suck out all the fluid with a turkey baster and pour in new D3 or 4 fluid. The stuff sitting in the reservoir is the first to get hydroscopic. I do that once a year. I also use PH strips a poster here turned me on to. Bought them on ebay for $5. I check once a year before I suck the fluid out. So far the fluid is doing really well. I detect no copper in my fluid with the strips. Granted this is not anywhere close to a brake flush but it may help a little.

This car is easy on the brakes and easy on the fluid.

 

Rust does impact on how efficient your brakes are. When the rotors get very rusty the rust is more abrasive than the non rusted cleaner areas of the rotors. The rust wares the pads away reducing the area of working pad. Often the rears of the rotors "the area you cannot" see is much rustier than the area you can see.

John (Britprius)

 

Pictures of front brake rotors off the Prius. Note how the visable surface compares with the hidden surface that probably has only 50% of it's area working.


John (Britprius)

 

I have the same problem. I notice the brakes are especially grabby after a rain storm. The interior portion of the rotors (cooling fins, area between the two plates) are so rusted. I really need to change the rotors; there's really nothing wrong with them otherwise, but I'd rather spend the extra $100+ to buy new rotors then continue to drive on these rusted out rotors. For all I know I could have to step on the brakes really hard one day and crush the rotor, which would likely cause more damage... So I'll probably replace them next year... or the year after that...