You have to take the uni out And depends what type of uni you have If it has circlips holding the caps in place your in luck can be pressed out, remove the yoke and replace the centre bearing, also be a good idea to replace the uni at the same time If it's got little crimps into the steel holding the uni caps in, you need to take the shaft to a driveline shop for them to do it Here is a pic of the non-serviceable type