Brake Fluid Loss and Brake TSB's

I posted in the other brake fluid thread, but I actually meant to post in this one. I don't think there is a problem with the brake fluid levels being reported. The center mark, the one circled in red "not this one" in the picture a couple of pages back, is the approximate correct level at Ig-On.

http://priuschat.com/forums/gen-iii...es-set-codes-when-flushing-3.html#post1405160

It is possible that Consumer Reports is picking up the caliper rattle and rear squeak noise. Owners have to nit-pick something and there are TSBs for both.

 

This may indicate a problem with Consumer Reports data collection rather than the Prius. As posted above it relates back to the voluntary brake recall which reflashed the brake system ECU to give the brakes a "different feel" and has nothing to do with brake fluid loss or any real braking problems.

The problem started when Prius owners started complaining about the fraction of a second loss of brakes when the car hit a rough patch of road while braking at low speeds. This caused the ABS system to engage and the car had to switch from regenerative to friction brakes for the ABS. Occasionally when this happened the brakes would go away for a few hundred milliseconds which was rather disconcerting the first time or two it happened to you.

But fortunately all you had to do was keep pushing on the pedal and the brakes would work fine. There were no accidents or other mishaps due to this.

Several people reported that they still had the problem after the recall. I didn't bother to have it done but I still have the notice which I will pass on the the next owner of my Prius.

If you want more information on this there are a lot of threads relating to it with some pretty good technical information. I do not consider it a reason to avoid buying a Prius, it is something to be aware of however.

 

That's better than my marginal art work in post #25.

The middle level would make sense to me as a normal operating level. I say that because think of what happens when you change your brake pads. Most of the time because of wear to the rotors, you have to compress each brake piston to get the pads to come off over the wear lip on the rotor. When you compress the piston it pushes brake fluid back into the reservoir. If the fluid level was at the full mark when you start this process, it would come close to over flowing after you do all 4 wheels. If you keep it around the middle mark, there's no chance of that happening.

Just a thought.

 

If the fluid reservoir has never been topped up, you can be pretty much certain it's not going to overflow with a new pad install. In my experience with a lot of Hondas at least: by the time you need to replace pads the level has dropped to the low mark. Push in the pistons to accomodate the new pads and the level goes back up to full.

Of course if the car's been in the dealership service department all bets are off. In that case you just need to be vigilant, and ready to baste some out as you go.

 

Hopefully not too late to report back... My Prius delivery was delayed for a week - stuck in Houston awaiting installation of floor mats.

Anyway here is a pic of the brake fluid after 48 miles (mostly highway)!

 

Good to know what the new ones are, thanks. I measured mine at 50K miles and they are still over 7mm in front and more than 8mm in the rear. Looks like I can make it to 100K miles easily.

 

As long as we are discussing brakes I though it might be helpful to mention that TireRack now stocks pads for our cars. They have both OEM replacement pads and ceramic pads. Might be less expensive than the dealer's parts department if you have to pay for them yourself. They also have rear rotors but no front rotors listed yet.

Brakes for 2010 Toyota Prius V

 

But do you have to go through the brake system dog and pony show to change the rears?

 

I have noticed the same issue as you, so you are not alone. I usually averaged 46-47 before the rear pad swap and I am now down to 45.

MB860 ?

 

Luscious Garage, one of the leading hybrid shops, quoted me 1hr labor ($120) plus the cost of brake fluid to perform a flush on my 2011. My selling dealer quoted $99 but I doubt the technicians there are familiar with brake fluid flushes on the Prius.

MB860 ?

 

Don't forget, winter formulation gas is here now. My mpg has dropped as of my last tank and it is noticeably harder to get it higher just due to the gas change. It happens nation wide in late October. It's guaranteed to drop your mpg and you "might" be seeing its effects instead of other changes like brakes.