This discussion should include what size TBU folks are using - 199 or 231. 231's seem to have more problems with ABS and soft pedal; very few examples of those issues with 199's.

Also, the primary benefit of TBU is not so much stopping power as it is higher thermal capacity and hence reduced likelihood of warping or fading when going down mountain roads.

The actual braking capacity is not likely to change unless you have crappy brakes - I was able to trigger ABS with the original brakes, and that's the limiting factor.

I'm very happy with my 199 upgrade, but again, not for the stopping power but for less fading and warping.

I agree with Leon. I went 231 route. And after changing my brake booster, T100 master cylinder, stainless braided lines, calipers, rotors, pads, and full bleed with new brake fluid... pedal has more travel but when brakes grab... They grab! First few drives after the full system change I'd press like gradual like normal then do a harsh jerk stop. Now I know when the grab happens. I get no shimmy coming down mountain roads like I used too.

The pedal travel, stiffness, and grab will vary on the many factors at play here.

Please let us know the outcome of your service visit. I’m having the EXACT same symptoms with the 231 TBU.

So I recently bought a 99 Highlander edition. I absolutely love it. It’s been supercharged and runs awesome. The only problem it has is the front rotors are warped (at least one is). So I wanted to replace them but have obviously heard the tundra upgrade is the way to go. I am on a pretty tight budget so I’m debating whether I should upgrade or not. I don’t tow and don’t plan on running anything larger than what I have now (265/75/16). However, I saw a guy online is selling his rotors, calipers, and pads off his 2008 tundra because he is doing a TRD brake upgrade. I am wondering if the second gen tundras brakes are the same as the first gen brakes that everyone is using for the upgrade. He is selling them for $275. From what I can tell it is everything I need for the upgrade so the price seems great. I’m just not sure they would fit and I’ve searched everywhere and can’t find any info on the second gen tundras.

What did you learn? What did you have to do to fix the problem?

If it helps, running the vehicle while doing the bleed can be all that's needed for this issue. Unless the issue is air trapped in the master cylinder.