[Si Coe]

I'm very puzzled about this.
As far as I know the car worked fine - but truth be told I don't tend to be one for slamming on the brakes anyway so I might not have noticed they weren't that good.
The same system in my D4 worked well though so don't think its the esc/motor. That said I can't think of any part in the B4 would prevent it stopping when you apply the brakes - its not like it has a one way!
Now it is possible the problem could lie in the radio set. I see no reason for that to be the case, but when I used the car I wasn't using that radio, so its the one thing I can't vouch for. But the radio worked fine in the Micro T so that seems unlikely too.
I'm pretty baffled, but I'm also sure that whatever the issue is, it should take seconds for the right person to spot and fix. Get to a club meeting and it will be sorted straight away - its too hard to sort over the phone/net but real easy to do first hand.