I recently bought a small (4' x 3') unbraked secondhand trailer, and until this week my Volvo was used to tow it. I Now have an Astra and need to weld up a Tow bar with towing ball. The sort that is mostly hidden bolted underneath the boot of the vehicle, with only the towing hitch ball on view at the back. Is there anywhere i can get plans for the dimensions of metal needed to make up a towing bracket for this vehicle ?

There does not seem to be any set plan for these as they are obviously dependant on the makeup of the rear of each different make of auto.

thanks