HOW TO

The Mini has had va­ri­ety of good and bad drive­shaft cou­plings...

Mini Magazine - - Contents -

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…

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