Replacing brake pad

Brake pads for most non-aggressive drivers last will over 100k miles in the Prius. I checked mine at about 50k miles and found almost no wear in the rear, and about 1/8th wear in front.

A more common problem actually is that the brakes pads are used so sparingly that the rotors rust in parts of the country where the roads are salted in the winter. Intentional use of the mechanical brakes is needed to prevent the rust !

So, I suggest checking the pads and not assuming replacement is required.

 

From what I've read, the front brake pads should easily last 100,000 miles.

So I'm skeptical about your dealer's claim that he replaced the pads at 46,000 miles.

In any event, it doesn't sound like you need new pads yet. But someone would have to check the existing pads to be sure.

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Despite what you may read on this forum, the Standard Prius has below average braking. It ranks in the lowly 11th percentile in 60 - 0 mph braking distances for the over 100 current model sedans tested by Consumer Reports.

So when my front pads wear out, I'm going to go for better stopping performance brake pads. I think the Standard Prius needs whatever advantage it might get from pads with better braking ability (I've already replaced my OEM tires with wider and better performing tires).

From what's available at TireRack, this would mean either the Hawk Performance Ceramic pads or the Hawk HPS Street pads.

I believe that apriusfan has put the Hawk Performance Ceramic pads on his Touring Prius (among his other mods).

 

hc167,

I drive in mountains too. Just as you describe, I switch to "B" for braking once my battery is filled up. Brake regen starts when you take your foot of the gas pedal, and increases in strenght as you push down on the brakes up to a maximum; any further braking is from the pads. Maximum regen is around 20 kW.

Checking the pads certainly seems like a reasonable place to start if braking performance is degraded, but I'll be surprised if it is the pads. What exactly have you noticed ?

 

On small hills use D. On steep mountain descents use B. If you aren't sure, then you probably don't need B mode. If you are driving the same roads repeatedly, you can tell if you need B mode by monitoring the state of battery charge. If you find all green bars at the end of the descent, then next time use B mode.

With either D or B mode, the Prius uses the brake pads only under 8 mph or in special circumstances, such as a panic stop or when regenerative braking isn't enough. Braking down a normal hill isn't one of them. Your brakes should be good for over 100,000 miles.

From your posts, it sounds like you are not familiar with brake work. Find a good mechanic that you can trust and get his opinion. I wouldn't trust a dealer that told you they replaced the pads as early as they did on your car.

Tom

 

As far as "brake work" I have to advise any Prius owner to use EXTREME CAUTION especially if they take their car to an independent who does not understand how the braking works

I've attached a couple of photos of the Prius brake schematic under normal and a failure mode. I've also attached the brake bleed procedure

If any "mechanic" tells you he "bled" the brakes on your Prius, punch him, call for a flat bed towtruck, and have your Prius taken to a Toyota dealership. The only way to safely and properly bleed the brakes on a Prius is to use the dealership scantool

 

I would use the OEM pads. They normally last over 100,000 miles, so there isn't much to gain by buying anything else. The OEM pads may be ceramic, but I'm not sure. I've heard mixed reports.

Tom

 

I suggest waiting for the battery icon to fill up completely with green before using B mode. If you don't, you are just losing out on some regen. 20 kw of regen power is enough to keep the car from speeding up on a pretty good decline, so thoughts of using B mode to save brake pads is not needed in my opinion until the battery is full.

I don't have an opinion on ceramic pads other than to say the OEM brakes on my Prius are just fine for my driving.

Check out this page from the most excellent Wayne Brown: http://privatenrg.com/#100kBrakePads

 

If you are nearly at the end of the hill before it hits full green, then leave the transmission in D. Otherwise you are wasting some energy that could otherwise be used to charge the battery.

Tom

 

The brake pads will only be used if more than a 20 kW drain off kinetic energy is desired, or the battery is full. Time I stopped repeating myself ...

 

You aren't quite getting a handle on the whole regenerative braking issue. Pressing the brake pedal does not engage the friction brakes except for the following:

1) Panic stop.
2) Loss of traction, such as hitting a bump.
3) Traction battery at or near the high limit.
4) Heavy braking in excess of regenerative limits.
5) Speeds at or lower than about 8 mph.

You can ride your brakes all the way down that hill and never use the friction brakes at all.

Tom