How to make undeformable cars deformable?

[Mr-Destroyer]

Some cars aren't deformable or get glitchy while deformable.
For example cars from user Brett are very good quality and has deformable suspension but body doesn't deform and is very hard(Only body parts glitch into each other).
Can someone explain how to make them deformable?
I don't disturb his/her work just modify it for myself to make it deformable.

 

[Ramys3434]

https://forum.rigsofrods.org/threads/is-it-possible-to-make-a-on-deformable-car-deformable.4343/ this might answer your question