2010 TRD Off Road Brake Issues

I have a 2010 TRD Off Road model Tacoma. When I brake while driving the pedal feels overly stiff and unresponsive. I am having trouble finding resources on this type of assembly. I've looked for other threads about this sort of problem with the TRD brakes but havent found much.

The pedal feel goes like:
1. First inch or so like any normal brake but no braking applied
2. Next inch pretty stiff and braking is only slight
3. Rest of travel extremely stiff and you have to push really hard to apply significant brake action

I've had my pads and rotors inspected and was told that they are in good shape. Before disassembling anything I bled the brakes and made sure that there was no air in them. I was fairly thorough and it seemed that they did not have any trapped air. Would this type of behavior be caused by air in the brake lines in the first place?

I've just removed the brake assembly from the engine bay by removing the four brake lines, disconnecting the pedal, and removing the four bolts in the foot well. I knew the TRD had special brake equipment but I was expecting a traditional brake booster and master cylinder setup when I pulled it out. Originally, all my research had indicated that the cause of the problem was likely a bad brake booster so I was a pretty surprised when I realized I didn't even have a brake booster!

My questions are:
1. Has anyone heard of this type of behavior for the TRD brakes?
2. Is there a simple fix or am I looking at complete replacement?
3. Is there a way to isolate the problem in the assembly itself or is it not a serviceable unit?
4. Where might I find a reliable source of replacement parts? (I am new to working on Tacomas)

Thanks!

 

I may be remembering wrong but I think it’s an electronic booster, not the typical vacuum booster.

 

Correct.

I would start by pushing the front caliper pistons back all the way. Then adjusting the rears properly.

Next I would do the techstream air bleed.

Then I would begin diagnostics. It could be the booster, its very expensive, but you have to eliminate the other possibilities. first.