Here are the instructions. The thinner black cable is string the thicker is a pneumatics tube that I have cut to about 5.5cm, it doesn't matter how long the string is. Please leave comments about what you think.
Quoting George Staples
That is a very cool idea. Looks like you just need the clutch system so you can use them :)
Thanks George, thats a great idea but sadly i probably wouldnt use these brakes as my car models are all larger scale so im not sure if it would create enough force. It was realy just as a help for anyone else who needed them. Thanks for the comment.