Bleeding 05 Prius brakes the old fashion way

Regarding the question whether debris would get into the line when compressing the piston, could someone help me visualize it since I have never seen it before? I imagine in normal braking operation the piston moves in and out to apply and release the brake pad. If so then what is the difference between normal operation of the piston and the compressing of it when changing the pads? Does the latter push the piston in further than the normal operation would do? If so then I could envision crud being carried from outside to inside, but why does the piston need to be pushed farther in to change the pads? Otherwise not enough space to install the pads? Thanks!

 

I'm not assuming anything. If his system is working properly (which he clearly states it is), there are no leaks in the seals. If there were leaks, then he would get air in the system and bleeding would be required. This would be evidenced by lower brake performance, evidence of leaking fluid, periodically having to add fluid and eventually brake failure. He has none of this.

Additionally, the seals have to be impervious to keep the system sealed (in essence, they are perfect if you have none of the above symptoms). In the case of these seals, they live a charmed life (no exposure to the environment and constant lubrication) which allows them to remain impervious for years. If "crud did get in the seal it would begin to leak almost immediately. They are already installed on all your cars and are functioning as new if you don't have any of the above symptoms (as to where you can get them, try your dealer or an auto parts store).

Yes, fluid would go out the nipple but any "crud" would not. So, there would be no benefit to opening the nipple but, opening the nipple would potentially (and most likely) let air in the system requiring a full bleeding of the system (a lot of extra work for no reason or benefit).

It really doesn't make sense. Unless the seals are leaking, there is no way for crud or debris to get in the system (closed system). Smart mechanics will tell you this to charge you more for your brake job. It looks like we'll just have to agree to disagree on this one.

 

Yes. In normal operation, the pads are retracted by a rubber gasket. During service, one would use a tool such as a screwdriver or C-clamp to push the piston in even further.

Correct! The caliper self-adjusts as the pads wear down, to accomodate the reduced thickness of the old pads. Since the new pads are thicker, they won't fit between the caliper and rotor as-is... the caliper needs manual adjustment in this case.

Sounds like you're ready to do your first brake job!

 

To minimize "crud getting into the line" I suppose one could clean the exposed surface of the piston before pushing it in, unless it's hidden or hard to reach?

 

Nope. If your o-ring is worn, the crud's already made its way into the cylinder. It's just waiting for a little push to work its way back up into the lines.

 

Couldn't replacing the pads introduce excess brake pedal travel for the first few times post-change, and in turn trigger alarms.

 

Nope. Since the calipers are self adjusting (as most are), you won't notice the change at the pedal... and I don't know that there's a sensor to detect pedal travel.

 

There should be no exposed piston to clean if all seals are intact. Any and every time you open the system you allow dirt to enter also moister. The filler cap should not be removed unless it is required to top up the fluid, but this should not happen unless there is a leak. As the pads wear the level will go down but it should not be topped up as when the pads are changed it will come back to full.

 

As an extra to the above I also instruct my dealer not to top up the brake system for three reasons.

(1) It is not needed.
(2) I do not believe they clean the area round the filler point before opening it allowing dirt to fall in.
(3) They almost certainly fill from a can that has been opened for weeks/months that may well be contaminated with moisture.

If I need to add fluid "because the fluid needs replacing" I always fill from a freshly opened sealed can.

 

Thanks, this saved me from being serviced at the dealership. I realized I had a problem with the lights coming on after working on one wheel. I saw that I couldn't bleed it and the repair manual said that you needed special tools and training to bleed the brakes. This worked good. Thanks again.

 

i am trying this with my 04 i just got,
i dont know if im doing wrong, but i cant get the lights to turn off(!, brake,abs)
put jumper clip in,i think i got the car in ready, hit brake pedal 8 times turn off remove jumper clip. turn car back on by barely depressing pedal.

ive been doing this for over an hr and i cant seem to get lights off,
i went to fuse box to change relays out and check fuses and same thing.

is there something that seems i am doing wrong?



EDIT

i think i could have found some problems, the larger bottom positioned blue abs relay is missing and the one next to it a green one seemed broken, a few pics ive seen shows a blue relay missing. i did get the pads and rotors changed and in the next day or 2 i will try to get rear drums changed, they had about 30-40% life left with.

knowing this and also the h/l light relay went out while i picked up car, i will source out a few of these relays and replace some. maybe this what the whole problem with the brakes to begin with

 

relay came in, put in and tried to clear code, it didnt work.

took to shop to get wireing/relays/ect looked at

seems large clear backed fuse with chips in it is bad, it seems the 30amp fuseable like from ig1 connector is bad. and when putting power manually to abs module assembly it makes no noise

im getting abs module assembly from junkyard and both fuses should be about another 100.

hopefully ill have up by next week

 

Hi all,

first post here, so first things first: thanks for the very helpful and knowledgeable forum!

I'm thinking of performing a caliper + 4 corners discs and pads change on my 96k miles, 2007 Prius (I'm in the UK and cars have dics at the rear here). The front right caliper has seized for some reason, discs are rusted, need new pads etc ... (think the car was used as a taxi in heavy traffic London before)

The cost of this being performed at Toyota's shop is, of course, ridiculous. (> 1,000£).

While I consider myself a competent DIYer and probably as geeky as it gets, that would pretty much be my first intervention on a car, so my questions to you guys are the following:

- jefftexas: how are things turning out with the dealer/stealer-ship ? What kind of cost/time are you incurring from the Toy Boys ?

- I know there have been some slight change to the way the braking system works in 2007, has anyone with a "Gen 2.2" Prius tried this procedure? Any reason to believe the car would behave differently?

- Given the cost I'm looking at ... seriously ... even if my dashboard turns into a Christmas tree on steroid ... resetting it won't set me back >1,000 £ ... right?

- As you are probably aware, the rest of the world drives on the WRONG side of the road, while we here are privileged enough to drive on the LEFT. Steering wheel goes to the right .... would that impact the order for bleeding the brakes given by dmphili? What is the reason for this order? (RR, LR, RF, LF)

Will post updates if I decide to dive in

 

Having replaced disc and pads myself on my own car (UK) "but not calipers" the work is as easy as any other car with similar mechanical set up.

For changing the calipers I would recommend buying a mini VCI of Ebay or Amazon I paid £23. This comes with Techstream the program the Toyota agents use and will allow flushing and bleeding brakes as well as giving and clearing the Prius fault codes, reading HV battery block voltages ect.

I bought quality named front and rear discs off Ebay the rears costing £16 for the pair, and fronts £40 the pair.

Any help I can give just ask or PM me.

John (Britprius)

 

Hi FXG
Welcome to PriusChat... You might want to do more research on here regarding that bad front right caliper... I've read on here some pretty sad stories about problems like that leading to the stealership having to replace brake ECU as well as other expensive components. The biggest thing to be aware of is that regenerative breaking means your expensive transmission directly interacts with your braking system and sometimes it's hard to diagnose problems because of that, especially if you're a stealership who'd rather just keep replacing super expensive parts until you solve the problem. So I suspect avoiding the dealership will avoid that part of the nightmare... But the more you can read about common problems with jammed brake calipers the better!

 

Brake hydraulic circuit to show you what you are up against.

If you are changing pads or discs or even removing a caliper without undoing the hydraulics disconnect the battery first. This could save you ejecting a piston or crushing your fingers.

John (Britprius)

 

That seems high. Even if it was in dollars it would be high.

I've done brake jobs before, either just disassemble/clean/relube of pads with some life still, or replacement. I've also tried replacing the brake fluid once or twice, but for the last few years have let the dealerships do it. Because I had a hard time getting all the air out, and dealership would do it for under $100.

With the intracies of Prius brake system, I'm leaning towards letting them do it, a pad refurb coupled with fluid change. Maybe I'm in for a nasty suprise, but I'd be suprised to see the bill for such service over $500 (Can/US).

 

The work the OP was quoting was for, calipers, discs, and pads. I was quoted over £400 just for discs and pads.

Edit. Just checked Toyota's fixed price servicing price for discs and pads front and rear =£460

John (Britprius)

 

Note in the diagram that your countryman BritPrius posted, that the hydraulic circuit for the two front brakes is slightly different. The stroke simulator, which creates the feeling of a conventional brake system during regen braking, is feeding the Left Hand front brake line. The Right Hand front brake line does not have that additional part. I suspect that asymmetry is the reason for the order, but I could be wrong. There are also unequal line lengths to the various brakes, so that may also be a factor.

 

Thanks for the help everyone!

BritPrius, thanks for the all the info, bought a VCI for 18 quid, will plug it in before doing anything and see if I can navigate through Techstream without too much trouble, will definitely give you a shout before I start!
460£ fixed price for front and rear servicing is quite a shock, the dealer is quoting me 358£ for the rear only! Does this mean the guy is dishonest? Don't want to jump to conclusion but that sounds like a joke.

Priuscamper, good point indeed. Actually the more I think about this the more I lean toward changing brakes and pads first, taking a good look at the caliper and checking for any obvious parts that could be replaced without having to actually disconnect the hydraulics (slid pin, etc ...)

Mendel Leisk, when you say you "tried"replacing the brake fluid, does this mean you weren't successful doing it on a Prius?

Nh7o, well spotted. I wonder if there are instructions or any kind of info in the Techstream software. Will see if I can find anything there.