HOW TO : Replace Front Brake Pads and Discs (Rotors) Prius Gen 2

Thanks for the write-up on changing the front disk brake pads and rotors! I just replaced both pads and rotors on my 2006 Prius for the first time at 132K miles. The job went fairly smooth. The only issue I had was getting both top bolts out of the brake pad mounts in order to remove the rotors. As an FYI, I did not remove the battery cable nor did I remove the fuses and I had no problems with warning lights when I started the car up once I was finished with the job. Here are a few pics.

 

Mylar, the reason for disconnecting the battery, or removing the relays is not to stop the car giving warning lights. The reason this is done is for safety to prevent crushed fingers, and to prevent the pistons from being ejected requiring the brakes to be bled. This is the reason Toyota call for this in the procedure. It does not guarantee fault codes will not be issued.
These problems will not arise every time work is carried out on the brakes, but there is a strong possibility. Doing the work without carrying out the correct method is to say the leased foolish, but it is your car, and hands so you may do as you wish. However telling people that the recommendations are not required is not doing them any favors, and could be putting them at risk of injury.

John (Britprius)

 

Very nice. I also flush out the holes in the caliper body. If you don't newly greased pins will just pick up all the rust and dirt that's in the caliper hole. That's the trick to making Napa & Auto parts stores rebuilt calipers last. There's so much slag and crap in those reman holes they never clean it out and a bath won't get it. Have to use a gun bore brush. Makes for a nice clean pin hole when your done. Happy clean & greased pins make for perfect brakes.

That and I would have applied grease to the hub mating surface as you roughed up the rust and that will just make it rust faster. I also apply grease to the mating surface to hub area of the tire. Just don't get outside of the rim and the hub & tire seal it permanently no grease leak out. When I go to put the tire back on I take out the center cover of the mag. After tire on I fill that hole up with synthetic grease and then put the cap back on. No leak out either.
Keeps hub castle nut from rusting and tire comes right off next time.

Better off using PB Blaster on a stuck bolts. That's the best penetrating oil and made for that purpose.
Blaster 11 oz. Penetrating Catalyst Lubricant-16PB-THD at The Home Depot

And all that suspension running gear can be kept from rusting by just spraying some grease on all those bolts and suspension parts. CSP spray made by PB Blaster is made for that and an excellent product. And use Black Magic Protectant rubber conditioner on all 4 cv boots and they'll last forever.
Blaster Corrosion Stop Protectant - PB Blaster

 

Excellent write up!!! Just did this (and a wheel bearing) yesterday with your first thread printed out as my guide!

Some strange loud beeping scared the begeezes out of me when finally starting the car up again...

Turned out to be the aftermarket radio complaining about loosing the station memory...

 

It was brake time... I am no stranger to doing a brake job. However, while trying to push the brake caliper piston back in using my trusty C-clamp, something happened. There was a snap or crack...like hard plastic broke. After searching locally I was able to get a new reman caliper overnighted. What I discovered is that my piston is not metal/steel, it is some type of phenolic resin. That was why is cracked. I don't know if all Gen 2's have this, but if so, I would recommend putting a pad over the piston and apply pressure to the pad, rather than directly to the back of the piston. This was a first for me!

 

Unless you have the VCI with Tech stream it is not a good idea with the Prius to open any part of the hydraulic circuit.
The hydraulic circuit is not like any other cars with ABS motors.
Below is the circuit With 10 electrically operated solenoids, and 7 pressure sensors. If any of the sensors see low pressure a brake fault code is issued, and this occurs if a bleed screw is opened. Techstream is required to bleed the brakes correctly (all lines and valves). There is a work around but this does not bleed all of the lines, and risks leaving air in the system. That in turn can lead to noisy operation (barking) when the brakes are applied.
Remember this is also part of the stability control system.
It is also not a good idea to work on the brakes without removing the two light blue relays in the fuse box as called for in the Toyota workshop manual. Disconnecting the 12 volt battery as a backup is good practice although not called for in the manual.
.brake map.jpg

John (Britprius)

 

Fantastic detailed procedure for replacing discs and rotors in Prius 2009. One note of caution for others. The two 17 mm caliper mounting bolts can be a real problem to remove. Two reasons are rust and use of blue permatex thread locking compound or worse. I have not been able to get them off and have used WD40, PB Blaster etc. Have also failed w breaker bars and extenders. Tried using my car jack as a tool to exert more force on the socket. Lastly, used MAP torch on bolts multiple times. All have failed. Tomorrow I am going to try the MAP followed by use of a Twin action 750 ft lb impact hammer/drill. Will let you know if it works.
As far as getting the rotor off. There are two small screw holes 6mm reported by another post that allows you to get it off without using a rubber mallet. My only question is what is the threading in TPIs (number of threads per inch?).
Again thanks for a great teaching lesson.

 

It's m8x1.25.

Some bugger musta used loctite on the caliper bolts, that's strange.

 

OK....well obviously I messed up. I failed to do solid research before working on the brake system. I failed to disconnect the battery before starting, that caused, at some point the brake system to push the piston out...then I broke the piston trying to push it back in, then had to replace the caliper. Now I have Traction Control, ABS, VSC and Brake lights on. I have tried some of the fixes reported in several places, including the paperclip trick to reset everything... no joy. It looks like I may be stuck taking it to the dealer. I am not happy about this...but even worse, I'm not happy because I caused the problem by not fully researching the persnickety brake system on the Prius. ...sigh.......

 

Sorry to hear your woes with the braking system, but you can still fix this without going to the dealer.
Purchase a mini VCI with Techstream, and bleed the brakes the correct way. There is a walk through for this within Techstream. This will also enable you to clear any fault codes.
You will then have the equipment for further use not just on your Prius, but any Toyota, and it should also work for engine problems on any OBD2 compliant car. At around $25 it is going to be cheaper than the dealer, and give you the satisfaction of solving the problem.

John (Britprius)

 

Thank you for giving the exact metric on the pre-drilled holes that allow you to easily remove the rotor.
Was finally able to get 17 mm caliper mounting bolts off w a dual impact hammer/torque wrench rated at max to 750 ft lbs. There wasn't any blue loctite and they were very clean for bolts in a 5 yr old car.
Question - Do you know any easy was to get the 4 x's 14mm axle bolts off. The flange of axle boot band does not allow any impact or the hundreds of other sockets to engage the bolt heads. Maddening job and very poor engineering IMHO. Thx
George

 

Used this post for a front rotor and pad change at 154K, including the suggestion from Britprius to leave the cap on the master cylinder. It's not any different from standard brakes once you follow the initial procedures in this post. I would add that the ABS motor relays are just pressed in. Mine were pretty tight and required more force to get out than I thought prudent.
Also, after disconnecting my 12V battery, I allowed the rear hatch to partially latch. I had to crawl in thru the back seats to release it so I could hook the battery back up.

 

^ A pair of of heavy, insulated rubber gloves comes in handy with the 12 volt: stuff the battery's negative cable into one, and lay the other across the hatch latching mechanism.

 

I thought you were going to say something about needing thick insulated gloves for 12V

Your advice sounds excellent

 

This description is good for Gen 1 Prius as well. When freeing the piston with a G clamp avoid trouble by using the old pad between the piston and the clamp. Thanks for a good clear description.

 

Its a C clamp not a G clamp.

In a G2 not neccessary to unbolt anything to disconnect
The 12 volt. Pry the red cover off of the positive pole
By prying on the side clips.
Under that cover are 2 wires that terminate in white plastic clips. Press the clip leve lever and pull the wires out the battery is now out of circuit. Toyota gives you the proper method use it.

 

Still have about 80% of the original pads on our 188K mile 2009 Touring.

 

excellent write up and we always love pix.

I have never removed the cap from a brake reservoir, and I've done literally thousands of brake jobs. also, remove the caliper from the mounting bracket first and it should be easier to access the 17mm mounting bolts. and yes, always use the old pad when pushing the piston in. it spreads the load around the edge of the piston. make sure your C clamp is centered on the piston so you don't cock the piston and jam it.

if when using the 8x1.25 bolts to push the rotor off the hub, it seems to be stuck, you hit the rotor with a large mallet and tighten the bolts a little more, hit and tighten until it comes loose. if they are badly rusted, you might just strip the threads out of the rotor if you don't use the mallet too.