Help with a Physics car project please

[Dubskiehrye]

Homework Statement

Engineering/Physics Car (Almost Exactly Science Olympiad Scrambler)

Relevant Equations

Ug--->K

Hello a group of students and I are trying to design a car with a wingnut breaking mechanism. However instead of the wingnut hitting the washer connected to the wood and stopping the threaded rod from rotating the threaded rod and wheels actually shift left while the wingnut stays stationary, and the right wheel hitting the wood is gthe thing that actually stops the vehicle. Does anyone have a fix to this?

 

[phinds]

Draw a picture

 

[Lnewqban]

Welcome, @Dubskiehrye !

Could you describe the braking mechanism in more detail?
Are you able to draw a basic diagram showing us the arrangement of the mentioned parts?

Perhaps the left brake is undesirably rotating the wingnut?
If so, safety wire may be a solution.