Motor Brake?

[Shark413]

Ok, I have converted several buggies/truggies and I have almost aways used mechanical brakes. I just prefer the feel and ability to adjust the bias. As an experiment I disconnected the mechanical brakes on one of my buggies and reset my Mamba Max ESC brake to 80% (it was set to zero, because I was using the 3rd channel for the mech brakes). When I applied the brakes and pushed the buggy I felt some resistance but the tires would still roll if I pushed hard enough. Thinking something was wrong, I grabbed my truggy and performed the same thing and again I could easily push the truggy with full brake. Thinking it had something to do with the mechanical setup I was using I grabbed my CRT.5 which I have always used motor only brake, again I could push the CRT.5 with some resistance but no lock-up, even at 100% brake on the ESC. I tried recalibrating the ESC with my radio, checked the EPA and trim, reset the radio to the default settings, same results. With mechanical brakes I could easily lock up all four wheels with my EPA set to max. Is it normal not to be able to get the motor brake to lock-up? I normally never run the mechanical brakes to the point where they lock-up but I could if I wanted to, which doesn't appear to be an option with motor only brake. Can anyone provide feedback regarding motor only brake? Are you guys able to set your motor only brake so the wheels almost lock-up?