A bit old thread, but still hoping for response.
I believe have the issue described, and have succeded in removing the plastic trim covereing the ratchet.
Is there a way to confirm that it is the ratchet that is broken without removing it. If so I'd like to order a spare one before removing the existing one.
Also, can the nut at the tip of the gearwheel of the ratchet be removed, and put back, without dismounting the chair from the car?
/Hans