Mechanic saying need new brakes what do i need to know ?

This is probably just a way to get money from you. Your brakes shouldn't be worn at such low mileage. They should measure the thickness of the pad and put it in writing, so you can call them out on their lie.

 

The most reliable way to find out would be to look in the owner's manual. Unfortunately, I don't have a 2013 owner's manual. Anyone out there have a 2013 owner's manual?

 

The inner pad has a copper "handle", with a little tang which will start contacting the rotor (and making lots of noise), when you've got maybe a millimeter left.

You can do quick check of remaining pad thickness yourself, even without removing the wheels, though pulling a wheel makes it easier. This is doable even with scissor jack, and a good exercise if you've not done it before, just to see what you're in for if you have a flat.

Loosen the lug nuts before raising the car, not completely, just enough that'll be easy to loosen them the rest of the way when the wheel's off the ground. Chock the wheel diagonally opposite. All this stuff is in the Owner's Manual. Torque for the lug nuts is 76 ft/lbs, and reinstall them in a star pattern.

Even without the wheel off: look through the wheel opening, with a good light, check for yourself. There's a backing plate and beyond that, touching the rotor, is the actual pad material. You should be able to eyeball it. The start out at 10mm, service limit is 1 mm, but anything around 2~3 mm I wouldn't wait too long.

I'd be inclined to use the Toyota pads.

The $64 question: when was the last time you had a complete brake inspection, not the visual check during tire rotation? Toyota USA tells you to do this every 3 years or 30,000 miles, whichever comes first.

I've attached the Repair Manual info.

 

"So I ask again does the Prius have some kind of sensor light that lets you know when your brakes need replacement before you start cutting into rotor or is it just that wear indicator bar scraping sound ?"

No.

 

In addition to the excellent replies thus far, bear in mind that your Prius uses regenerative braking so the pads will last much longer and wear much more slowly than those in other cars your mechanic may be accustomed to servicing. One other special thing you should know, if your master cylinder is pressurized like the one on my '12 Plug-in there is a procedure for relieving the pressure before even opening the cap. It's a job you may want to save for Toyota.

 

Read through the attachment in post #5. Toyota's Repair Manuals are remiss, in that they show everything that can be done with the brake, but they don't spell out blow-by-blow what portion of that should be done at a brake inspection. Honda's better in that regard, their Shop Manuals have a definitive section titled Brake Inspection, and the same term is used in the schedule. From years with Honda, their manuals, personal experience, what I've seen at dealerships, this is what I'd see as a brake inspection:

1. Lift the calipers off the rotors (brake lines still attached).
2. Inspect and clean of the pads and shims, check thickness. Reassemble of pads and shims with proper lube in the faying surfaces (points of contact between components).
3. Clean caliper, especially contact points with pads, inspect for cracks/damage. Lube the caliper points that contact the pads. Check brake lines for cracking/twisting/rust.
4. Pull out caliper glide pins, clean and relube with proper lube, and lightly lube the boots as well. Reassemble.
5. Check rotor thickness and runout against spec. Requires micrometer and dial indicator (with magnetic base). (I do sometimes goof off on this when DIY'ing, especially if I've done it before, everything was ok and there's no pulsing when using the brakes.)
6. Reassemble everything and road-test.

Lubes I use, neither kosher but no problems with either:

1. Faying surfaces, pads to shims to caliper: Permatex Anti-Seize. (silver grease/paste)
2. Caliper slide pins: Sil-Glyde Brake Lubricant. (transluscent grease, looks like Vaseline)

If you were to DIY the Prius brakes, there are some specific, additional "gotchas" you have to be careful of, specifically:

1. Precautions need to be taken to avoid the brakes "pressurizing" while the calipers are off the rotors.
2. The integrated parking brake on rear caliper makes them a little tricky, you really need to get the piston orientation right (and make sure it STAYS right), to avoid brake drag problems down the road.

 

49k miles and you're down to 3mm? Were your miles ever rolled back? People here don't usually need brakes until 100k miles....unless they get corroded. Very unusual for wear related.

 

The front's are relatively conventional. Whoever's doing it, a few tips:

1. Disconnect 12 volt before any disassembly, and leave it off for the full duration of the work, when everything is reassembled, pump the brake pedal multiple times before reconnecting the 12 volt. This will ensure there's no pressurizing events while the calipers are off the rotors, and the car won't detect excess pedal travel.

2. The front caliper piston is a high tech plastic: when pushing it back in use something that it's contact with the full diameter of the piston, avoid point loads.

 

That's a very decent deal.

 

$109 at the dealer is great, parts run $80+

 

Yeah I was thinking the same thing. I paid over $100 CDN at dealership for (2010 Prius) replacement rear pads. I checked McGeorge Toyota (online US retailer) and it was discount price $40, before shipping. Typically in Canada when going to a dealership, for brake job with pad replacement, I wouldn't get out of there under $200, front or rear. And that was maybe 20 years back, I just DIY now, unless it's something like a caliper rebuild (which I've never encountered).