The Mini has had variety of good and bad driveshaft couplings...
In this instalment we demonstrate how to change your driveshaft.
The originals were the yoke type where a rubber-wrapped cross was lightly U-bolted between the diff output and the end of the driveshaft. Squidge and play in the rubber allowed the required flex and also absorbed some torque effects during gear changes and on/off power delivery. While this flex provided a slightly smoother drive, the couplings were somewhat limited in their ability to cope with increased power when the Cooper Ss were introduced. Early 1070S cars had the rubber couplings, but they were soon changed for the Hardy-Spicer universal joint which continued on the performance models into the ’70s and on automatics into the ’80s.
For many years Hardy-Spicers were the driveshaft of choice when it came to competition or spirited use, but fitting them required special diff side covers and they have a different method of bolting the outputs to the H-S specific diff. With the extra fafffactor involved, in recent times the joint of choice has been the pot-joint, and virtually all modern performance differentials are fitted with pot-joint outputs. Capable of transmitting massive amounts of power, they are simple and reliable; but they won’t actually fit through the subframe when assembled. Removing the driveshaft from the joint is simple when it’s in a vice on the bench, but difficult on the car – even the Churchill special tool isn’t 100% reliable. We’ve all snipped the tie wrap and split the joint to pull the greasy driveshaft and then sworn at it upon reassembly as the boot won’t sit straight as you do up the new tie wrap… Which brings us back to the Hardy-Spicer, which will fit though the driveshaft hole in the subframe.
Those clever chaps at MED have produced an adaptor to enable the use of H-S joints with the ubiquitous pot-joint diff outputs, so it is now possible to have your cake and eat it. No special covers or seals, a standard differential, and the ability to disconnect and remove the driveshafts without getting covered in grease. Okay, undoing four small nuts takes longer than snipping a cable tie, but there’s no perishable rubber boot to unexpectedly fail an MoT and the joint is rebuildable by swapping the universal joint at its core for a new one.
It may seem odd that step one in changing the driveshafts is to drain the oil, but depending on the oil level and the angle of the car the diff outputs are submerged – pull the pot joint out and the oil in the sump will drop out of the hole you’ve just created. Trust me, you only do that once…