Need to bleed?

I haven't looked, but does it have a normsl bleeder valve?

SCH-I605 ?

 

Absent someone who has direct experience on Gen1's, my suggestion would be to try it tha normal way, of course with the key off and out of the ignition. I'll be doing mine here soon so I'm interested to know the answer myself.

SCH-I605 ?

 

I suggest you contact threeprongpaul. He is an expert on this.

 

Hi Mitch,

If I remember the setup right, then provided you have a way to watch the reservoir so it never goes dry, you can bleed the rear very easily. You don't need to pump the brakes, just turn the ignition on, if the brake pressure pump comes on wait for it to stop, then just lightly hold the brake pedal down with something, open the bleeder, and let the air out. Close the bleeder when the air's out. Done. The pump will give you a continuous flow as long as you need the bleeder open.

Did I mention keeping an eye on the reservoir? If you don't have a way to know when it's getting low and top it off, nothing will stop the pump from running it dry if you have the bleeder open long enough. Here's the thing about the Gen 1 brakes: if you ever get to the point where the pump sucked in air at the reservoir, your DIY project just turned into a non-DIY project (or, at the very least, a challenge exercise involving the service manuals, the New Car Features manual, and the wiring diagram, or a Mini-VCI and Techstream).

-Chap

 

Bleeding Brakes after losing all fluid from brake fluid reservoir. Car is 2001 Prius with 249,600 miles.

Background: Right Rear brake line connection leaking, all brake pressure lost. Brake fluid reservoir was dry. It was not clear if master cylinder was out of fluid but the brake line was full of air as we found out later. ABS light flashing and check engine light on along with PS and triangle with exclamation. Scan code reader did not pull any codes, most likely due to scanner not being adequate for prius technology.

I tried to bleed brakes using traditional method of push brake pedal, open valve, wait for pump to turn on. Pump would not turn on after many attempts at this.

After much research of Gen 2 and Gen 3 brake issues, I decided to try this process.

1. Placed copper wire jumper between 4 and 13 on OBD-II plug

2. Inserted key, power on to display only, not engine start. Turn off, turn to power on. All warning lights immediately cleared.

3. Opened RR bleeder screw with hose connected to reservoir with small amount of brake fluid in it to prevent air from sucking back in (just in case it did).

4. Pushed brake pedal about ½ ways down waiting for pump to turn on. I did this about 12 times, taking about 2 seconds between each pump. Slowing pushing down 1 sec, let up about 1 sec, repeat. At some point the electric pump turned on and my assistant was able to see fluid and air coming out. The pump did not run continuous while the brake pedal was depressed. It would run about 3 secs, turn off. I would get off pedal, push it again slowly and about 3 times of this the electric pump would come on. We closed the valve, filled the brake reservoir and kept repeating until no air was seen. The RR line had a large amount of air so it is possible the master cylinder had air. We bleed all four wheels using the above process and it worked.

5. After all wheels where bleed, then push brake pedal down 8-10 times.

6. Remove jumper wire.

7. Push and hold brake pedal down.

8. Start car, test drive.

9. Test drive found no pulsing or odd brake behavior and no warning lights reappeared.

 

You can bleed a gen1 like a normal car no need for the dealer.
Works best if car is ON and READY. Have a helper pump pedal and you open bleeder valves as if it was a Corolla.

Gen2 and newer you pretty need Techstream to bleed properly.

Make sure entire brake system is back together before bleeding
(i.e. don't have front calipers dangling off the car without pads or pistons will shoot out)

 

I'm impressed by the willingness to do that experiment, but anyone else reading this thread needs to know that procedure isn't complete, even for a Gen 1. The ABS actuator may still contain air that can't be bled without operating its internal valves in a specific sequence, which is what the Techstream software does in the brake bleeding function. (In the case of the Gen 1, the manual makes it sound as if only one solenoid might need to be operated, which might be about easy enough to do by probing the actuator's electrical connector, if you had the wiring diagram, the New Car Features Manual (which is where the hydraulic diagrams are) and a certain amount of daring, but not Techstream. Apparently with Gen 2 it got harder. I haven't heard of anyone actually trying it on a Gen 1, and anyway with Mini VCI so cheap these days, a lot of people are just using Techstream and being done with it.)

The downside of having a brake system that seems well bled except maybe inside the ABS actuator would be a possible brake performance surprise right when you least want one.

It's possible in your case no air got into the ABS actuator and this procedure will have worked for you without any issue, but anyone later reading this thread needs to decide whether to count on your luck.

-Chap