Yaris 2007 Rear Brakes issue

[ricardo-cr23]

Hello!

I have a Toyota Yaris 2007 Sedan 1.5L with ABS brakes. The issue I have is that I have to adjust the rear brakes really often. I start noticing they loose when the parking brake lever starts loosing up.

Looks like it only happens on the left side (I disassemble the interior, and I look at the parking brake pull rod sub-assembly, and left side one is loose).

What I have done so far:

- Replaced whole drum, brake shoes, wheel brake cylinder, springs, the brake shoe strut set.
- Adjusted parking brake lever nut
- Bled the brakes, making sure no air is in the system (not sure if this has something to do with it)

I took the car to government annual inspection, and the report said there is a braking difference between rear brakes.

My mechanic told me that it could be one of the valves that inject brake fluid, but I am not sure about this.

What can I do to find the faulty part?