U/J is a universal joint, meaning a cruciform running in paired bearings, like a Hardy Spicer joint, as opposed to a C/V, or constant velocity, joint. The issue is that on a Berk these drive shaft are off offset lengths. The shorter the length, given the steering lock, the more the two bearings can wind up, especially if they are not mounted opposing each other on a shared shaft. The play is designed to be taken out of the system by a sliding spline on the drive shaft. All well and dandy when used in something deflecting like a drive shaft from engine to rear axle. The technology is over its limit on the Berk front suspension, really.
Many small cars had to deal with this problem on rear suspensions, and often a cushdrive coupling was included. Likewise on front wheel drive, which test the system further than most rear drives, the joint play take up is more important. Saab and such had rubber joints. Even the Mini had rubberised cruciform initially, before finally switching to CV joints after experiments with Hardy Spicer to take the excess power demands of the Cooper S.
Not content with that there is a tendency for the drive shaft nut to undo. This has ended in a wheel disappearing on private tour down the road on more than a few Berks over the years. All rather embarrassing. Its easy to see why Berks get modified, as the cheap production is great, in that it uses basic parts bin resources, but the package is not as good as the sports car image suggests. Hence a change of engine, front drive, disc brakes, or imp stuff, steering rack, move of fuel tank to rear with pump and a stiffen up of the body. A production car turned into a kit car, really. The ultimate, and normally no way back mod, was to dump a caste iron 4 pot Mini engine and subframe into the front, with some bonnet blimps, or extra chassis to raise the car. By this time much of the Berk is actually residing in the bin. But its part of Berk history whether you like them, or not.
