Swapping brake hydraulic pump

rlin78 was the first person I knew of to do it from below. Said about ten hours. Did you find that thread?

 

I hate crawling around the underside of cars. So I did mine from the top.If you can, get the A/C evacuated. And if you open up the system as suggested, duct tape the open tubes and hoses. I don't remember how I did it, but I managed to not destroy anything of the pump, wiring, tubes, hoses. It can be done from the top, the factory repair manual can help.

 

Were you able to successfully replace the pump?
When I had to replace mine, I dropped the pump assembly from below the vehicle. Didn't want to mess with the AC system and refilling it afterward. I tried removing the pump assembly from topside, but wires and AC lines, brake lines in the way, even if the engine were lifted and rocked forward, it seemed to me, to have been too much trouble to mess with the AC system, risk bending hard tubes on the brake system or AC line. The risk of accidentally breaching a brake or AC line outweighed the PITA of removing the CV axle from below.

I had to remove the passenger side wheel assembly, disc brake assembly, rotor assembly, and CV axle. There is almost enough clearance to remove it from the bottom side of the vehicle, but unfortunately just not enough clearance no matter how you rotate the pump assembly, without removing the passenger side CV axle. With the axle removed, the pump assembly, can be rotated as necessary for removal.

After I removed the brake pump assembly, I swapped out the electric motor from the assembly (with a $20 brake assembly part part from the savage yard). The electric motor from the brake pump assembly that came out of my Prius had worn the contact sleeve where the magnet brush resides down about 1.5 to 2cm. Enough to lose contact for meaningful electrical conduction. The salvage yard part had very little wear. One of the best $20 I've spent in a long time. The one that came out of my car was completely filled with dust particles. The paper gaskets that are part of the assembly will be impossible to find. I resorted to placing them into my work copier, and cutting them by hand. They are only there to prevent external environmental dust from entering the motor assembly. A light coat of gasket material helps upon reassembly.

Reinstallation from the bottom side is not so bad. The pump assembly is heavy and will be testy when lifted back into place. Take your time.

Brake bleeding consisted of using the "KMOON Mini VCI Car ODB Diagnostics Scanner ODB2 USB Interface Scan Tool for Toyota TIS Techstream Diagnostic Cable & Software" I bought on Amazon. Even this took some software manipulation to get it to work on my Wndows 7 laptop. Specifically you have to generate a new registry entry on your computer to get the software to recognize the scan tool. But once you do, it's worth the money spent (because now you can also look into your vehicle's hybrid battery health).

The brake bleeding cannot be completed without the scan tool (or the official Toyota Techstream tool). The software is needed to actuate the pump motor to fill and bleed the accumulator, and then also to bleed the brake system at each wheel. You will want to bleed the brakes at each wheel after replacing the brake pump assembly.

This entire repair took me 3 days...because I'm old and slow, and like to take my time. Any questions, drop me a line. Oh, and keep that auxiliary battery on a trickle charger while you're doing all this. Personally I kept my battery on the repair/charge cycle using a NOCO Genius 3500 charger (allows you to desulfinate the battery plates). $60 investment saved me from having to buy a $200 replacement battery.