Brake Pad replacment?

In reply to yesterday's post from me in this thread and reply from Dr. Fusco, I can provide an update.

"What's the noise like? When, in the braking process, do you hear it? Does it go away? Where does it seem to come from (one wheel, under the hood, etc?)
Help us help you."
__________________
Evan E. Fusco, MD

I didn't hear any brake noise on the ride home yesterday or the ride in today. So, I'm thinking there may have been grit (sand, etc.) and/or moisture that contributed to the noise I could hear when lightly braking on Wednesday commute home. I've read the posts about the accumulator, etc. and I'm guessing that wasn't/isn't a problem (yet, anyway) and I don't as I didn't hear any noise when at a resting stop with foot on the brake pedal (no chirping or barking sound either). Only heard the noise when lightly braking to a stop.

I'll have more driving opportunities tonight and over the weekend so that will provide a better test of whether the noise has completely disappeared.
Jim

 

It depends on how hard you are braking, but generally with moderate braking that's correct.

The Prius uses one of the motor/generator as a generator and uses the spinning wheels and the momentum of the vehicle to turn the generator. The force required to turn the generator and generate electricity slows the wheels and therefore the car. This electricity is pushed into the battery to recharge it.

Now if you want to stop faster than the maximum force the generator can allow, the Prius will also apply the brake pads to assist in stopping faster. Also if you press the brake pedal sharply (panic stop) the Prius applies the brake pads.

I'm not positive, and maybe one of the local experts can back me up here, but I think if the anit-lock braking system kicks in then the Prius reverts to brake pads as well.

 

Ouch!, I don't know if I've ever seen 7 MPG on my Prius.

Perhaps you mean 7 MPH?

 

Dr. Fusco,

Hey, I was thinking. You know if that E.D. Doc thing doesn't work out for you, you could be one hell of a service adviser for a Toyota dealership!

 

That is great to know that brake pads last a long time on the Prius. I guess it all depends on how hard the driver uses the brakes. With my 1995 Taurus SHO (I still have it), my first set of pads were still good per PA. state inspection at 123K. Unfortunately, around 140K my rear left brake line was clogged up and it made my rear calipers stick on heavy braking. I went home one afternoon and discovered my rear rotors were smoking and almost glowing red. So, I ended up replacing all my lines, calipers and rotors and pads at 140K.

For the Prius, I also expect to get over 100K, since majority of my driving is highway.

 

I inherited a 2005 Prius with 38,000 miles and would like to add that the front brake pads were squeaking and I have been putting off a pad replacement for about a year now. I checked the pads and they are almost gone, so I will replace them within a week.

I have replaced disc pads multiple times and have no issues doing so. I was hesitant to attempt changing the prius pads since it's a hybrid.

If I remember, I will post a followup to let the board know if it was no problem. I did gain confidence though when I saw someone note it's just like changing pads on any other car.

Anyway, would like to add also, that I knew the previous owner of the car very well (family) and he would hit he brakes consistently very hard and forceful to the point it would scare me.

I won't go too much into this personal story on the internet, my point is - brake pads can wear quickly on a Prius due to driver behaviour.

 

Is "opening the bleed ports to retract the calipers" a normal thing? For instance if I go to a generic brake place like Brakes Plus or something, will the 16yr old tech start to do this and make me tow it to a dealer to get a $80 bleed unless I tell him not too?

Like in my last car, I just said I want brakes, I want ceramic, I'll see you in an hour. What do I do with the Prius?

 

You need to also be concerned with the fact that a Prius can activate the accumulator pump when it is off. If this happens during the brake job, the caliper pistons can be ejected and the trip to to dealer will be for much more than $80. Either disconnect the 12v battery or remove the proper fuse to prevent this possibility.

You bought a high tech car which requires some training in it's behavior and sometimes special tools. Toyota dealers have an expensive computer to access and control the braking system. Normal brake job garages do not have these tools or knowledge.

JeffD

ps. My 2004 Prius is now at 171,500 miles on the original brakes.

 

Another great post. Thanks! I bought my Prius recently used, so I do not know the status of the brakes or how the last ownered drove it. So I am thinking of getting them checked and/or replaced just for piece of mind. Once they are replaced, I hope I can go 6 digits on a single set!

So basically: disconnect the +12v battery, and do not open the bleed ports.

I am a techie and know it is a high tech car. I am currently mucking around with its 3 comm networks to sniff out what I can.

 

I changed the front brake pads on my Prius today, it was easy.
It took me almost exactly one hour from gathering tools, to job completion, cleanup, and test drive.

I found it to be simple to replace the brake pads on My Prius and identical to what I expected from working on previous cars with disc brakes. I specifically mention this because I went crazy trying to google "Prius brake pad replacement" when trying to find out if I could change the pads on my own or if there was something special or different regarding thios process on a hybrid. Reading previous posts in this thread gave me the confidence to finally change the darn pads. Thanks folks!

Here is a breakdown, I used the following tools:

A hydraulic jack. ($25)
Chocks on both rear wheels. ($10)
Electric Impact Wrench ($60)
Socket Wrench - Set of Sockets. ($20)
Ceramic Pads ($39).
A rubber mallet ($5 - helps in removing slide pin w/ a couple taps)
A "dial" torque wrench ($20)
Disc Brake Pad Spreader($6)

I owned all the tools prior to today, only had to buy the brake pads - just left prices in case someone would find helpful in estimating. My tools are from various places (Wal-mart, Pepboys, Harbour Freight, Sears, etc) and of varying manufacturers and were bought at different times in the past. Tools come in all different price ranges, qualities, and manufacturers.....

An electric impact wrench is my favorite when it comes to removing lugnuts and putting back on - just don't tighten them too much and always use a torque wrench to complete tightening! Removing a tire takes literally seconds with an impact wrench.

I do not know the exact spec for torqueing a lugnut on the Prius - I set to 85 ft-lbs (I'm certain it's not the correct number), if someone could update me on the correct number I would be most appreciative.

Additional notes/details:
Disc spreader worked perfectly, no issues.
I retracted piston as far back as it would possibly go (had to, with the new pads)
With the Prius you have to remove both slider pins to replace brake pads. I mention this because I only had to remove one slider pin on my old accord (per wheel) to replace pads because piston housing and caliper would slide enough to remove pads.
Reason for removing both pins on Prius?
Brake hose slack is nominal, caliper can't slide enough when only one pin is removed. No biggie, just mentioning the details.
Removing the slider pins was very easy, I used a socket wrench and gave a few brisk taps to socket handle with a rubber mallet (while holding the wrench tightly). Each pin took a matter of seconds to remove and this was the first brake pad replacement on the car.
What impressed me the most was the condition of the rotor (I now have 58,000 miles on the car) and rotor is in beautiful shape.

Sidenote: I have replaced rotors on previous cars in the past. It's generally easy and not as expensive as many people would have you believe - usually $35-$40 per wheel for a nice shiny meaty rotor (installed by you). Which I consider nothing when most car payments are much more per month.

As mentioned above, I used the more expensive ceramic pads and not the semi metallic ones. Personally, I like ceramic better. Plus there is no anti squeal shim (The thin metal plate your supposed to put brake grease on) with the ceramic pads I bought, it's designed to not need one. In fact, grease was not even included with the pads and instructions specifically mention it is not required or even recommended for the pads. FYI, I used some spare grease on the piston housing shims located around the caliper just for poops and giggles brakes are quiet, smooth, and work vey nice.

All told - I had no difficulty removing/replacing the brake pads on my Prius.

In fact, it was the easiest pad replacement I have ever done - simply because slider pins were so easy to loosen (I've had some tough ones to work with in the past). For reference, I have previously owned and replaced brake pads on a Chevy Cavalier and Honda Accord. Prius is my third car to ever change pads.

One last note, after pads were done I turned the vehicle on and pumped the brakes (while in park) a few times. Brake pedal was spongy at first then piston reset and all was well. Test drove - brakes work perfectly.

Thus is my experience.

 

It's a good idea to lubricate both caliper slide pins to avoid sticking. Our brakes get very little exercise and if the pins corrode, the pads will wear unevenly.

JeffD

 

Re: Brake Pad replacement?

The torque spec is 76 ft.-lb.

Your previous post mentioned that the pads were worn due to the prior driver behavior. Did you measure the thickness of the front rotors to see whether they were below minimum spec (22 mm is new, 20 mm is minimum)?

I recommend that the 12V battery should be disconnected before brake work commences, to ensure you don't have a problem with the skid control ECU logging DTC or running the brake pressure accumulator pump while you are hard at work.