Technical Resource - CV Joints
The drive shaft constant velocity joints couple the drive shafts from the gearbox drive flanges and the rear up right wheel bearings via the rear upright drive cup. There are a number of different types of CV joints used on Formula Ford Zetec's, some have three bearings, some have four.

It is important to service the bearings on a routine basis perhaps, once at the end of every season. This will help to reduce friction, reduce wear and helps to minimise water ingress. Neglected CV joints are often the root cause of a snapped drive shaft.
Servicing CV Joints