Sorry my friend, that statement is not true.
Out of adjustment rear brakes would NOT cause excess pedal travel. That's not how hydraulic systems work.
The increased travel in the slave cylinder would be equalized by more brake fluid entering the master cylinder from the reservoir.
I have a 1963 car that has manually adjusted drum brakes. It used to have them all the way around, until I swapped some discs onto the front.
As they went out of adjustment, the pedal travel would increase. To the point you'd have to 'pump' the brake quickly. Adjust them, and the travel decreased.
Once you depress the brake pedal even a little, the piston moves and cuts off the small hole leading to the reservoir. At that point, more fluid cen't enter the system. If it did, it would somehow have to flow in from the unpressurized reservoir and into the pressurized brake system (pressure caused by the piston being pushed).
Out of adjustment means there's too much slack at the back brakes, which in turn means that more fluid needs to be pushed into the system to shove the brake shoes out far enough to engage the drum. Disc brakes are self adjusting because there's nothing really forcing the pads to retract from the rotor, once extra fluid has been pushed into the calipers to account for wear on the pads, they jsut stay that further bit out.
But drum brakes are different. The shoes have springs on them. Any extra fluid required to push them out far enough to hit the drums doesn't stay, it gets forced back to the reservoir once the pedal is fully released, by those hefty springs on the shoes. You have to push that extra fluid each time, which results in more pedal travel. Unless the adjuster holds the shoes further out.
And like I said, the 4Runner automatic adjusters do work, unless someone has taken them apart and put them back together wrong. I put mine together loose as can be, and after 20/30/40 pulls on the handbrake the snugged up properly. You could feel it happening. The first 2/3rds or so the handbrake was going full travel, no resistance at the top. Then it started to hit resistance at the top, and slowly worked its way down to roughly mid stroke, where it stopped changing. Fully adjusted. This also happens automatically when you use the brakes, any time the shoes move too far, a lever reaches out past the next pawl and pulls it back, tightening the adjuster one 'notch'.
