Brake pump/accumulator/actuator running more frequently than before

Normal wear, the brakes leak a bit more. Eventually they may have to replace the master brake cylinder, but I wouldn't rush out to have that done until necessary. It's pretty expensive. DO have a look at each wheel to see if you can see "wetness". It shouldn't happen, but you never know.

If you're worried, take it to the dealer to see that the mechanic finds. Again, a master brake cylinder is quite expensive on a Prius.

 

The length of time it runs depends somewhat on how much time has passed since it last ran. When you noted run times of only 3 seconds, was that perhaps after only a brief stop? The 5-10 second time seems normal after an overnight or longer stop, at least in my experience.

I wish it didn't do that stupid trick. Why waste battery charge and add needless wear to the expensive pump merely because you've opened the door for some reason, when you aren't necessarily even going to drive the car?

 

This sounds like it could fall under the recall that was affecting many 2010 Prius vehicles.
Check out this link :

New GenIII brake recall affects 87,000 cars | PriusChat

 

Long brake pump actuator has nothing have to do with master cylinder leaking failing it's doing its job. Most likely it's compensating for the brake pad wear, think of it when you get in the car for the first time the brake pump actuate until the pads are touching the rotors so the lower the pads the more time the actuator takes to pump up to pressure. And when ever you leave the car the system brakes depressurize releasing all the pressure and the brake pad are free.

You now wonder why you have to remove the battery, place your key 30 ft away and take out the abs relay to change the brakes pads?

 

The above contains several notions that aren't at all like what you will find if you look in the New Car Features Manual (on techinfo.toyota.com) to learn how your car works. In no particular order:

• The function of the accumulator pump is not to move the brake pads closer to the rotors. A Gen 3 has disc brakes all around, and disc brake calipers have a self-adjusting property: every time you use the brakes, the pistons extend as far as they have to, but they only return as far as the rubber seal springs back (roughly 0.3 mm), so as long as the calipers are working properly that gap remains constant throughout the wear life of the pads.
• There is nothing that happens when you leave the car to depressurize the brakes. (At least, there isn't in Gen 1 or Gen 2, and I would be surprised if that was different for Gen 3.) When you have released the brake and exited the car, the pads stay right where they were (that is, free for the fronts, and applied for the rears if you have put on the parking brake).
  
• However, accumulator pressure may drop slowly while you are away from the car, just because the seals in the system may not be perfect. Fluid that passes the seals, internally, simply returns to the reservoir, and will be pumped back into the accumulator the next time you wake up the car and the pump runs.

I wholeheartedly recommend the New Car Features Manual as a great read for anyone who'd like to have a good understanding of how this fascinating car works.

-Chap

 

Holy moley, talk about differences between the generations:

1. Gen 1: master cylinder ~ $600, but there's a $55 piston/seal kit for old-timers who don't mind a little brake fluid on their fingers ...
2. Gen 2: no rebuild kit offered, but the master cylinder itself drops to a very reasonable $124.
3. Gen 3: master cylinder, ABS actuator, and accumulator have all been integrated into one magnificent assembly for an equally magnificent $1852.00.

Goood grief! At least it saves you all the hassle of deciding which part you need....

this integrate-everything-into-super-assemblies trend isn't something I'm totally sold on ....

-Chap

 

Agree. I gather that Prius wheel bearings are another egregious example.

 

The "Prius wheel bearings" issue is not just a Prius issue. The bearings are replaceable on a lot of new cars, but they come already mounted in a hub.

 

Going to need a pump and master......... : ( I know how it goes......

 

... although with less of a difference between generations, and far less of a real total difference in cost. Even Gen 1 already had "generation 3 hub bearing assemblies" in the rear (just to keep things confusing, the bearing industry has HBA 'generations', not related to Prius 'generations'), Gen 2 Prius has them at all 4 corners and AFAIK Gen 3 is just the same. Only place Prius ever used anything different was the front bearings on Gen 1.

And the difference in real cost is a lot smaller; yes, you can get a front bearing for a Gen 1 around $40 compared to a couple hundred for the integrated assemblies. Then you get to add up the labor for four stages of press work to get the old one out and the new one in, compared to four bolts, swapping the HBA and drinking a beer. At the end either one might have the slight advantage, depending on the choice of beer.

But seriously, $1852 for a Grand Unified Brake Thing that has neither a rebuild kit nor a -84 reman version offered?

Not long ago I was idly thinking about when I might upgrade my Gen 1 to a Gen 3, but I keep learning things like this and thinking the Gen 1 is still running pretty well....

-Chap

As long as this thread's been resurrected, I'll add one more factor that can figure in to that initial pump run seeming longer:

Age of the 12 volt battery.

Remember that first, open-the-driver-door, pump run happens before you've made the car READY, so it's all on the 12 volt battery to supply that power. An older battery will definitely run the pump slower and take longer to finish.

I just replaced the original battery in my 2010. For its last week or two, I would open the driver door and the brake pump would sound like a dying windup toy, and need like half a minute.

 

Good factor to add-in.

I am noticing the same behavior too, every 2-3 brake pedal presses, I can hear the pump running for 2-3 sec ., most times would be a quick one, open-the-door: It would be longer. I can't remember how it used to be when I got it used 6 years back with 70M on-clock(now around 136M, 90% freeway).

Mine is also coupled with squaking/quacking noises too, adding more to paranoia. Now and then in winter: horrendous cold rattle (terrible shake, feels like asymmetric rotation.

Also diagnosed with recently: timing cover oil seepage (will figure out much oil lost when i take it for oil change this week)

ChapmanF,, do you notice this pump running on 2-3 brake pedal press for 2-3 secs (same as OP)

 

It depends on so many factors it really kind of defies simple descriptions. In general, I'd say yeah, depending on how much attention I'm paying and the ambient sound level around, the times when I happen to notice it will be around "every so many" uses of the brake, and for "a couple seconds" each time. I'm not convinced that trying to pin it down more closely than that has much benefit, other than offering something to obsess over.

I read somewhere that doctors sometimes get patients who are hyper-observant of the color and shape of their poo, so the docs have to keep reassuring them "yeah, well, you know, it depends on lots of things."

 

Could be head gasket.

Don't get talked into a reseal just yet, there may be bigger issues.

Check the oil level yourself.

EGR or intake manifold cleaning ever done? Again, could be head gasket.

 

My mechanic just told me there is active code C1256 but no warning lights, which is strange, over last few days I can hear the brake pressure thing working overtime but thought it's just my paranoia,.

Carfax service history says "Intake manifold replaced" at 44k Miles (Now at 136K Miles), so wondering if EGR cleaning has to be done,.

 

Step one, I would check the EGR pipe condition, per @NutzAboutBolts video #16, linked here:

Nutz About Bolts Prius Maintenance Videos | PriusChat

With 136K miles and a cold-start knock, don't delay.

 

Quick update

Thanks, I will have to start looking at it now that car has come back from workshop after brake zjb fix, sitting at dealer for 3.5 weeks took a toll on battery, had to fork out 300$ for new one as this would enable dealer to brake bleed.

 

This is what's supposed to enable the dealer to brake bleed: